Three of these four numbers leave the same remainder when they are divided by 7. Which is the odd one out? 24, 59, 87, 40

Divide each by 7 and look only at what is left over. $24=7\times 3+3,59=7\times 8+3$ and $87=7\times 12+3$ — all three leave 3. But $40=7\times 5+5$ leaves 5, so 40 breaks the pattern. The traps: 24 is the only number here below 50 and the only multiple of 4; 59 is the only prime; and 87 is the largest. Each of those is a real difference, but none of them is the property the question asks about.