Sarah had a total of 351 white and blue marbles. She used
45 of her white marbles and bought another 49 blue marbles. The number of blue marbles she had then become
13 the number of white marbles. How many less blue marbles than white marbles did she have at first?
| |
White marbles |
Blue marbles |
| Before |
5x3 |
|
| Change |
- 4x3 |
+ 49 |
| After |
1x3 |
|
| Comparing marbles in the end |
3x1 |
1x1 |
| |
White marbles |
Blue marbles |
| Before |
15 u |
1 u - 49 |
| Change |
- 12 u |
+ 49 |
| After |
3 u |
1 u |
The number of white marbles in the end is repeated.
LCM of 1 and 3 is 3.
Total number of white marbles and blue marbles
= 15 u + 1 u - 49
= 16 u - 49
16 u - 49 = 351
16 u = 351 + 49
16 u = 400
1 u = 400 ÷ 16 = 25
Number of less blue marbles than white marbles at first
= 15 u - (1 u - 49)
= 14 u + 49
= 14 x 25 + 49
= 399
Answer(s): 399
