Question

A rational no. is such that when you multiply it by5/2 and add 2/3 to the product you get -7/12 what is the no.?

Answer 1

A/Q,
Let the req. no. be x.
Then,
5x/2+2/3=-7/12
Therefore,
5x/2 = -7/12-2/3
5x/2= -15/12
Hence, 5x= -15/6 = -5/2
Hence, x = -1/2 Ans.

Answer 2

as per the question,

x*5/2+2/3=-7/12
x*5/2= -7/12-2/3
L.C.M. =12
x*5/2= -7-8/12
x*5/2= -15/12
x*5/2= -5/4
x= -5/4*2/5 (ie the reciprocal of 5/2)

therefore, x= -1/2

-1/2 is that rational number... it can be verified by substituting the value of x with -1/2...
hope it helps...