Question

If Y is a sum of two variables,one of which varies directly with X and other varies inversely with X.When X=1 then Y=-1 and when X=3 then Y=5.So calculate Y when X=6.

Answer 1

Answer:

11.5

Step-by-step explanation:

y = ax + b/x

-1 = a + b ( for x=1 , y =-1)

5 = 3a + b/3 ( for x=3 , y=5)

multiply 1st by 3

-3 = 3a + 3b

-8 = 3b -b/3

-8 = 8b/3

b = -3

-1 = a -3

a = 2

y = 2x  - 3/x

putting x=6

y = 12 - 1/2

y = 23/2

y = 11.5