Selina solutions

Selina solutions

Grade 7

Unitary Method (including Time and Work) | Exercise 7(C)

Question 10

Q10) Shaheed can prepare one wooden chair in 3 days and Shaif can prepare the same chair in 4 days. If they work together, in how many days will they prepare :

(i) one chair?

(ii)14 chairs of the same kind?

Solution:

Shaheed’s 1 day’s work = \frac{1}{3}

And Shaif’s 1 day’s work = \frac{1}{4}

Both one day’s work = \frac{1}{3}+\frac{1}{4}=\frac{4+3}{12}

∴ Both can prepare the chair in = \frac{12}{7}days=1\frac{5}{7}days

One chair is prepared in = 1\frac{5}{7}days

∴ 14 chairs will be prepared in = \frac{12}{7}\times14=24\ days

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subject-cta

Question 10

Q10) Shaheed can prepare one wooden chair in 3 days and Shaif can prepare the same chair in 4 days. If they work together, in how many days will they prepare :

(i) one chair?

(ii)14 chairs of the same kind?

Solution:

Shaheed’s 1 day’s work = \frac{1}{3}

And Shaif’s 1 day’s work = \frac{1}{4}

Both one day’s work = \frac{1}{3}+\frac{1}{4}=\frac{4+3}{12}

∴ Both can prepare the chair in = \frac{12}{7}days=1\frac{5}{7}days

One chair is prepared in = 1\frac{5}{7}days

∴ 14 chairs will be prepared in = \frac{12}{7}\times14=24\ days

Still have questions? Our expert teachers can help you out

Book a free class now

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subject-cta
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