Ncert solutions

Ncert solutions

Grade 8

Linear Equations in One Variable | Exercise 2.2

Question 10

Q10) The number of boys and girls in a class are in the ratio 7 : 5. The number of boys is 8 more than the number of girls. What is the total class strength?

Solution:

Let the number of girls be x.

Then, the number of boys = x+8

According to the question, \frac{x+8}{x}=\frac{7}{5}

\Rightarrow5\left(x+8\right)=7x

\Rightarrow5x+40=7x

\Rightarrow5x-7x=-40

[Transporting 7x to L.H.S and 40 to R.H.S]

\Rightarrow-2x=-40\Rightarrow\ -\frac{2x}{-2}=-\frac{40}{-2}

[Dividing both sides by -2]

x = 20

Hence the number of girls = 20 and number of boys = 20 + 8 = 28.

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subject-cta

Question 10

Q10) The number of boys and girls in a class are in the ratio 7 : 5. The number of boys is 8 more than the number of girls. What is the total class strength?

Solution:

Let the number of girls be x.

Then, the number of boys = x+8

According to the question, \frac{x+8}{x}=\frac{7}{5}

\Rightarrow5\left(x+8\right)=7x

\Rightarrow5x+40=7x

\Rightarrow5x-7x=-40

[Transporting 7x to L.H.S and 40 to R.H.S]

\Rightarrow-2x=-40\Rightarrow\ -\frac{2x}{-2}=-\frac{40}{-2}

[Dividing both sides by -2]

x = 20

Hence the number of girls = 20 and number of boys = 20 + 8 = 28.

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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