Question

3. If x and 3.5y vary directly and * = 7 when y = 10, find x whey y is =15​

Answer 1

Answer:

10.5

let x = k ×3.5y

when x = 7, y =10

k ×3.5× 10 =7

k=7÷ 10 ÷ 3.5 = 0.2

so k= 0.2

when you= 15

x = 3.5 × 0.2 × 15 = 10.5