Discussion

Explanation:

Let the numbers be x and 156 – x

$\frac{7x}{5(156-x)}=\frac{5}{2}$

⇒ 14x = 25 × 156 - 25x

⇒ 39x  = 25 × 156 

⇒ x = 25 × 4 = 100

∴ The first part is 100.

Hence, 100.

Alternately,

Let the numbers be a and b.

Hence, a + b = 156, and

$\frac{7a}{5b}=\frac{5}{2}$ 

⇒ $\frac{a}{b}=\frac{25}{14}$

⇒ a = 25/39 × 156 = 100.

Hence, 100.

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