Zane has 172 marbles and Ethan has 370 marbles. How many marbles must Ethan give to Zane so that Zane will have 90 less marbles than Ethan?
| |
Zane |
Ethan |
Total |
| Before |
172 |
370 |
542 |
| Change |
+ ? |
- ? |
|
| After |
1 u |
1 u + 90 |
542 |
The total number of marbles remains unchanged after Ethan gives to Zane.
Total number of marbles
= 172 + 370
= 542
Total number of marbles in the end
= 1 u + 1 u + 90
= 2 u + 90
2 u + 90 = 542
2 u = 542 - 90
2 u = 452
1 u = 452 ÷ 2 = 226
Number of marbles that Ethan must give to Zane
= 226 - 172
= 54
Answer(s): 54
