Andy has 253 marbles and Seth has 490 marbles. How many marbles must Seth give to Andy so that Andy will have 69 less marbles than Seth?
| |
Andy |
Seth |
Total |
| Before |
253 |
490 |
743 |
| Change |
+ ? |
- ? |
|
| After |
1 u |
1 u + 69 |
743 |
The total number of marbles remains unchanged after Seth gives to Andy.
Total number of marbles
= 253 + 490
= 743
Total number of marbles in the end
= 1 u + 1 u + 69
= 2 u + 69
2 u + 69 = 743
2 u = 743 - 69
2 u = 674
1 u = 674 ÷ 2 = 337
Number of marbles that Seth must give to Andy
= 337 - 253
= 84
Answer(s): 84
