Selina solutions

Selina solutions

Selina solutions

Grade 7

CHAPTERS

3. Fractions (Including Problems)

4. Decimal Fractions (Decimals)

5. Exponents (including Laws of Exponents)

6. Ratio and Proportion (Including Sharing in a Ratio)

7. Unitary Method (including Time and Work)

11. Fundamental Concepts (Including Fundamental Operations)

12. Simple Linear Equations (Including Word Problems)

13. Set Concepts (Some Simple Divisions by Vedic Method)

14. Lines and Angles (Including Construction of angles)

17. Symmetry (Including Reflection and Rotation)

18. Recognition of Solids (Representing 3-D in 2-D)

Q1) Find the S.I. and amount on :

(i) Rs. 150 for 4 years at 5% per year.

(ii) Rs. 350 for 3\frac{1}{2} years at 8% p.a.

(iii) Rs. 620 for 4 months at 8 p. per rupee per month.

(iv) Rs. 3,380 for 30 months at 4\frac{1}{2} % p.a.

(v) 600 from July 12 to Dec. 5 at 10% p.a.

(vi) Rs. 850 from 10th March to 3rd August at 2\frac{1}{2}% p.a.

(vii) Rs. 225 for 3 years 9 months at 16% p.a.

Solution:

(i) P = Rs. 150, R = 5% per year, T = 4 years

∴ SI = \frac{PRT}{100}=\frac{150\times5\times4}{100}=Rs.30

And Amount = P + SI = 150 + 30 = Rs. 180

(ii) P = Rs. 350, R = 8% p.a

T = 3\frac{1}{2}years=\frac{7}{2}

∴SI=\frac{PRT}{100}=\frac{350\times8\times7}{100\times2}=Rs.98

Amount = P + SI = 350 + 98 = Rs. 448

(iii) P = Rs. 620

R = 8 p per rupee per month = 8% p.m

T = 4 months

∴ SI = \frac{PRT}{100}=\frac{620\times8\times4}{100}=\frac{19840}{100}=Rs.198.40

∴ Amount = P + SI

= 620 + 198.40 = Rs. 818.40

(iv) Principal (P) = Rs. 3380

Rate = 4\frac{1}{2}\%\ p.a=\frac{9}{2}\%

Period = 30 months = \frac{30}{12}years

SI=\frac{PRT}{100}=\frac{3380\times9\times30}{100\times2\times12}=\frac{1521}{4}=Rs.380.25

Amount = P + SI

= 3380 + 380.25 = Rs. 3760.25

(v) P = Rs. 600, R = 10% p.a

T = July 12 to Dec 5

July = 19 days

Aug = 31 days

Sep = 30 days

Oct = 31 days

Nov = 30 days

Dec = 05 days

Total = 146 days

=\frac{146}{365}=\frac{2}{5}years

∴SI=\frac{PRT}{100}=\frac{600\times10\times2}{100\times5}=Rs.24

∴ Amount = P + SI = 600 + 24 = Rs. 624

(vi) P = Rs. 850,

R = 2\frac{1}{2}\%=\frac{5}{2}\%\ p.a

T = 10th march to 3rd Aug

March = 21 days

April = 30 days

May = 31 days

June = 30 days

July = 31 days

Aug = 03 days

Total = 146 days

=\frac{146}{365}=\frac{2}{5}years

∴SI=\frac{850\times5\times2}{100\times2\times5}=Rs.8.50

∴ Amount = P + SI

= Rs . 850 + Rs. 8.50 = Rs. 858.50

(vii) P = Rs. 225, R = 16% p.a

T = 3 years 9 months

=3\frac{9}{12}=3\frac{3}{4}years=\frac{15}{4}years

∴SI=\frac{PRT}{100}=\frac{225\times16\times15}{100\times4}=Rs.135

∴ Amount = P + SI = Rs. 225 + Rs. 135 = Rs. 360

Still have questions? Our expert teachers can help you out

Book a free class nowFractions (Including Problems)

Exponents (including Laws of Exponents)

Ratio and Proportion (Including Sharing in a Ratio)

Unitary Method (including Time and Work)

Fundamental Concepts (Including Fundamental Operations)

Simple Linear Equations (Including Word Problems)

Set Concepts (Some Simple Divisions by Vedic Method)

Lines and Angles (Including Construction of angles)

Symmetry (Including Reflection and Rotation)

Recognition of Solids (Representing 3-D in 2-D)

Q1) Find the S.I. and amount on :

(i) Rs. 150 for 4 years at 5% per year.

(ii) Rs. 350 for 3\frac{1}{2} years at 8% p.a.

(iii) Rs. 620 for 4 months at 8 p. per rupee per month.

(iv) Rs. 3,380 for 30 months at 4\frac{1}{2} % p.a.

(v) 600 from July 12 to Dec. 5 at 10% p.a.

(vi) Rs. 850 from 10th March to 3rd August at 2\frac{1}{2}% p.a.

(vii) Rs. 225 for 3 years 9 months at 16% p.a.

Solution:

(i) P = Rs. 150, R = 5% per year, T = 4 years

∴ SI = \frac{PRT}{100}=\frac{150\times5\times4}{100}=Rs.30

And Amount = P + SI = 150 + 30 = Rs. 180

(ii) P = Rs. 350, R = 8% p.a

T = 3\frac{1}{2}years=\frac{7}{2}

∴SI=\frac{PRT}{100}=\frac{350\times8\times7}{100\times2}=Rs.98

Amount = P + SI = 350 + 98 = Rs. 448

(iii) P = Rs. 620

R = 8 p per rupee per month = 8% p.m

T = 4 months

∴ SI = \frac{PRT}{100}=\frac{620\times8\times4}{100}=\frac{19840}{100}=Rs.198.40

∴ Amount = P + SI

= 620 + 198.40 = Rs. 818.40

(iv) Principal (P) = Rs. 3380

Rate = 4\frac{1}{2}\%\ p.a=\frac{9}{2}\%

Period = 30 months = \frac{30}{12}years

SI=\frac{PRT}{100}=\frac{3380\times9\times30}{100\times2\times12}=\frac{1521}{4}=Rs.380.25

Amount = P + SI

= 3380 + 380.25 = Rs. 3760.25

(v) P = Rs. 600, R = 10% p.a

T = July 12 to Dec 5

July = 19 days

Aug = 31 days

Sep = 30 days

Oct = 31 days

Nov = 30 days

Dec = 05 days

Total = 146 days

=\frac{146}{365}=\frac{2}{5}years

∴SI=\frac{PRT}{100}=\frac{600\times10\times2}{100\times5}=Rs.24

∴ Amount = P + SI = 600 + 24 = Rs. 624

(vi) P = Rs. 850,

R = 2\frac{1}{2}\%=\frac{5}{2}\%\ p.a

T = 10th march to 3rd Aug

March = 21 days

April = 30 days

May = 31 days

June = 30 days

July = 31 days

Aug = 03 days

Total = 146 days

=\frac{146}{365}=\frac{2}{5}years

∴SI=\frac{850\times5\times2}{100\times2\times5}=Rs.8.50

∴ Amount = P + SI

= Rs . 850 + Rs. 8.50 = Rs. 858.50

(vii) P = Rs. 225, R = 16% p.a

T = 3 years 9 months

=3\frac{9}{12}=3\frac{3}{4}years=\frac{15}{4}years

∴SI=\frac{PRT}{100}=\frac{225\times16\times15}{100\times4}=Rs.135

∴ Amount = P + SI = Rs. 225 + Rs. 135 = Rs. 360

Still have questions? Our expert teachers can help you out

Book a free class nowLido

Courses

Race To Space

Quick Links

Terms & Policies

Terms & Policies