a=y
b=x
revise:
y varies directly w/ x and y=28 when x=7, find x when y=5
y=kx
k=y/x
k=28/7
k=4
y=4x
5=4x
4x/4=5/4
x=5/4 or x=1.25
Answer:
a = 4b and b = 5 / 4
Step-by-step explanation:
From given statement , we observe that
a ∝ b
a = kb eq(1)
where k is a constant.
given that
a = 28 when b = 7
28 = k(7)
k = 28 / 7
k = 4
Putting above value in eq(1), we have
a = 4b
Now , we have to find value of b when a = 5.
Putting in above equation, we have
5 = 4b
b = 5 / 4 which is the answer.
