Question

‘A’ varies directly as the sum of two quantities
‘B’ and ‘C’. ‘B’ in turn varies directly as ‘x’ and ‘C’
varies inversely as ‘x’. When x = 1 or 2, A = 3. Find
the value of A when x = 4.

Answer 1

Answer:

Step-by-step explanation:

A varies directly as sum of B and C

=> A= k(B+C) (k is some constant)

now, B varies directly as x

=> B=k*x

and C varies inversely as x

=> C=k/x  

 A= k(B+C)

=>A=(k*x + k/x)

=>A=px + q/x -----(k = p & q )

so, for x=1,

3= 1p + q/1

and for x=2,

3=2p + q/2

solving for p and q,

p=1

q=2

=>A= x +(2)/x

So, for x=4,

A= 4.5