Question

If y is 5 when xis 2.5 and y varies directly with x, find y when x is 10.

Answer 1

You write y = 5 when x = 2.5 so divide 5/2.5 so when y = 1 , x = 2 so when x = 10 y= 20

Answer 2

ANSWER:  

If y is 5 when x is 2.5 and y varies directly with x, then value of y is 20 when x is 10

SOLUTION:

Given, y is 5 when x is 2.5 and y varies directly with x,

We need to find y when x is 10.

Now, according to given information, y  x

y = cx → (1)

where c is proportionality constant.

Now put, y = 5 and x = 2.5 values in (1) to find value of c

5 = c x (2.5)

$\mathrm{C}=\frac{5}{2.5}=2$

Now, put x = 10 to find y in (1)

y = c × x

y = 2 x 10

y = 20

hence, value of y is 20 when x is 10.