When 70% of a number x is added to another number y, the sum becomes 165% of the value of y. When 60% of the number x is added to another number z, then the sum becomes 165% of the value of z. Which one of the following is correct?

On re-checking, the earlier conclusion (d) was a mistake.
From 0.7x + y = 1.65y, we get 0.7x = 0.65y ⇒ y = \frac{14}{13}x, so y > x.
From 0.6x + z = 1.65z, we get 0.6x = 0.65z ⇒ z = \frac{12}{13}x, so z < x.
Thus the correct order is z < x < y.

• (a) z < x < y — Matches the derived order. Correct.
• (b) x < y < z — False because z < x. Incorrect.
• (c) y < x < z — False because y > x and z < x. Incorrect.
• (d) z < y < x — False because y > x. Incorrect.