Mathematical Reasoning
A farm had 348 white rabbits and grey rabbits altogether. After 102 white rabbits are sold, the remaining whi…
Question 1 · Multiple choice
Question
A farm had 348 white rabbits and grey rabbits altogether. After 102 white rabbits are sold, the remaining white rabbits are as many as the grey rabbits. How many white rabbits and grey rabbits were there at first?
Options
- A.200 white and 148 grey
- B.225 white and 123 grey
- C.230 white and 118 grey
- D.210 white and 138 grey
- E.220 white and 128 grey
Correct answer
Explanation
Step 1: Set up the equations
Let w = number of white rabbits at first, and g = number of grey rabbits at first.
Equation 1 — total rabbits: w + g = 348
After selling 102 white rabbits, the remaining white rabbits equal the grey rabbits:
Equation 2: w − 102 = g
Step 2: Substitute and solve
From Equation 2: g = w − 102
Substitute into Equation 1:
w + (w − 102) = 348
2w − 102 = 348
2w = 348 + 102 = 450
w = 450 ÷ 2 = 225 white rabbits
g = 348 − 225 = 123 grey rabbits
Check: After selling 102 white: 225 − 102 = 123 = grey rabbits ✓
Answer: 225 white rabbits and 123 grey rabbits
| Option | White | Grey | Sum | After selling 102 | |
|---|---|---|---|---|---|
| A | 200 | 148 | 348 | 98≠148 | ✗ |
| B | 225 | 123 | 348 | 123=123 | ✓ |
| C | 230 | 118 | 348 | 128≠118 | ✗ |
| D | 210 | 138 | 348 | 108≠138 | ✗ |
| E | 220 | 128 | 348 | 118≠128 | ✗ |