Elyse had a total of 423 silver and red marbles. She used
47 of her silver marbles and bought another 33 red marbles. The number of red marbles she had then become
15 the number of silver marbles. How many less red marbles than silver marbles did she have at first?
| |
Silver marbles |
Red marbles |
| Before |
7x5 |
|
| Change |
- 4x5 |
+ 33 |
| After |
3x5 |
|
| Comparing marbles in the end |
5x3 |
1x3 |
| |
Silver marbles |
Red marbles |
| Before |
35 u |
3 u - 33 |
| Change |
- 20 u |
+ 33 |
| After |
15 u |
3 u |
The number of silver marbles in the end is repeated.
LCM of 3 and 5 is 15.
Total number of silver marbles and red marbles
= 35 u + 3 u - 33
= 38 u - 33
38 u - 33 = 423
38 u = 423 + 33
38 u = 456
1 u = 456 ÷ 38 = 12
Number of less red marbles than silver marbles at first
= 35 u - (3 u - 33)
= 32 u + 33
= 32 x 12 + 33
= 417
Answer(s): 417
