Correct option is C
Given:
P + Q = Rs. 6,40,000
P saves 60% of his salary, so his savings are 0.6P and his expenditure is 0.4P.
Q saves 40% of his salary, so his savings are 0.4Q and his expenditure is 0.6Q.
Their expenditures are the same, so we have 0.4P = 0.6Q.
Solve for P and Q:
0.4P = 0.6Q,
we get P/Q = 0.6/0.4 = 3/2.
Therefore, the ratio of P's salary to Q's salary is 3:2.