Opal and Gwen have some cookies each. If Opal gives Gwen 29 cookies, Opal will have
12 as many cookies as Gwen. If Opal gives Gwen 19 cookies, they will have an equal number of cookies. How many cookies does Opal have at first?
|
Case 1 |
Case 2 |
|
Opal |
Gwen |
Opal |
Gwen |
Before |
1 u + 29 |
2 u - 29 |
1.5 u + 19 |
1.5 u - 19 |
Change |
- 29 |
+ 29 |
- 19 |
+ 19 |
After |
1 u |
2 u |
1.5 u |
1.5 u |
Total number of cookies that Opal and Gwen have
= 1 u + 2 u
= 3 u
Number of cookies that Opal and Gwen each has in the end is the same.
Number of cookies that Opal and Gwen each has in the end in Case 2
= 3 u ÷ 2
= 1.5 u
Number of cookies that Opal had at first is the same in Case 1 and Case 2.
1.5 u + 19 = 1 u + 29
1.5 u - 1 u = 29 - 19
0.5 u = 10
1 u = 10 ÷ 0.5 = 20
Number of cookies that Opal has
= 1 u + 29
= 1 x 20 + 29
= 20 + 29
= 49
Answer(s): 49