Last Monday, Pierre had twice as many beads as Elijah. Today, Pierre gives 21 of his beads to his brother. Now, Elijah has twice as many beads as Pierre. How many beads does Elijah have?
| |
Pierre |
Elijah |
| Before |
2x2 =
4 u |
1x2 =
2 u |
| Change |
- 21 |
|
| After |
1 u |
2 u |
The number of beads that Elijah had at first and in the end remains unchanged. Make the number of beads that Elijah has the same. LCM of 1 and 2 is 2.
Number of beads that Pierre gives to his brother
= 4 u - 1 u
= 3 u
3 u = 21
1 u = 21 ÷ 3 = 7
Number of beads that Elijah has
= 2 u
= 2 x 7
= 14
Answer(s): 14
