Mathematical Reasoning
Mao had 360 more rubber seeds than Sun. When Sun gave 46 rubber seeds to Mao, Mao had 5 times as many rubber …
Question 1 · Multiple choice
Question
Mao had 360 more rubber seeds than Sun. When Sun gave 46 rubber seeds to Mao, Mao had 5 times as many rubber seeds as Sun. How many rubber seeds did Mao have at first?
Options
- A.439
- B.469
- C.499
- D.549
- E.519
Correct answer
Explanation
Step 1: Set up variables
Let Sun's seeds at the start = S
Then Mao's seeds = S + 360 (Mao had 360 more)
Step 2: Apply the transfer (Sun gives 46 to Mao)
After the transfer:
- Sun has: S − 46
- Mao has: (S + 360) + 46 = S + 406
Step 3: Use the 5-times condition
After the transfer, Mao has 5 times as many as Sun:
S + 406 = 5 × (S − 46)
S + 406 = 5S − 230
406 + 230 = 5S − S
636 = 4S
S = 636 ÷ 4 = 159
Step 4: Find Mao's original seeds
Mao at first = S + 360 = 159 + 360 = 519
Check: After transfer: Sun = 113, Mao = 565. 565 = 5 × 113 ✓
Answer: Mao had 519 seeds at first