Question

The mean proportional of a and b is 10 and the value of a is four times the value of b. If a>0,b>0, find the value of a+b

Answer 1

Hi ,

It is given that mean of a and b = 10

( a + b )/2 = 10

a + b = 20 ---( 1 )

a is four times of b

a = 4b ---( 2 )

Substitute ( 2 ) in equation ( 1 ) , we

get

4b + b = 20

5b = 20

b = 20/5

b = 4

Put b = 4 in equation ( 2 ) , we get

a = 4 × 4 = 16

Now ,

a + b = 16 + 4 = 20

I hope this helps you.

: )

Answer 2

Answer:

20 is the answer of addition of a+b