Hilda and Betty have some puffs each. If Hilda gives Betty 25 puffs, Hilda will have
78 as many puffs as Betty. If Hilda gives Betty 6 puffs, they will have an equal number of puffs. How many puffs does Betty have at first?
| |
Case 1 |
Case 2 |
| |
Hilda |
Betty |
Hilda |
Betty |
| Before |
7 u + 25 |
8 u - 25 |
7.5 u + 6 |
7.5 u - 6 |
| Change |
- 25 |
+ 25 |
- 6 |
+ 6 |
| After |
7 u |
8 u |
7.5 u |
7.5 u |
Total number of puffs that Hilda and Betty have
= 7 u + 8 u
= 15 u
Number of puffs that Hilda and Betty each has in the end is the same.
Number of puffs that Hilda and Betty each has in the end in Case 2
= 15 u ÷ 2
= 7.5 u
Number of puffs that Hilda had at first is the same in Case 1 and Case 2.
7.5 u + 6 = 7 u + 25
7.5 u - 7 u = 25 - 6
0.5 u = 19
1 u = 19 ÷ 0.5 = 38
Number of puffs that Betty has
= 8 u - 25
= 8 x 38 - 25
= 304 - 25
= 279
Answer(s): 279
