Question

If x and y vary directly and x = 20 when y= 35,find the value of x when y=21?

Answer 1

Answer:

x=34

Step-by-step explanation:

as it is said above

x=20 and y=35

in the second case , given,

y=21 and we need to find x

here in first case x+y=55

from this

substitute y =21 in this

we get ,

x+21=55

x=55-21

x=34

hope it helps. u

Answer 2

GIVEN :-

• x and y vary directly with each other.
• x = 20 when y = 35.

TO FIND :-

• The value of x when y = 21.

SOLUTION :-

Here in the question it is given that , x and y vary directly. therefore we can say that,

$\\ : \implies \displaystyle \sf \dfrac{x_1}{ y_1} = \dfrac{ x_2}{ y_2}$

• x1 = 20
• y1 = 35
• x2 = x
• y2 = 21

$\\ : \implies \displaystyle \sf \frac{20}{35} = \frac{x}{21}$

By cross multiplication we get,

$\\ \\ : \implies \displaystyle \sf 20 \times 21 = x \times 35$

$: \implies \displaystyle \sf 420 = 35x$

$: \implies \displaystyle \sf x = \frac{420}{35}$

$: \implies \displaystyle \sf \underline{ \boxed{\displaystyle \sf \: x = 12}}$

$\therefore\underline {\displaystyle \textsf {The value of x when y is 21 is 12.}}$