Bobby, Billy and Andy had a total of 381 pens at first. After a week, the number of Bobby's pens became 3 times the number of pens he had at first. The number of Billy's pens decreased by 251. Andy had half as many pens as he had at first. In the end, the three boys had the same number of pens.
- How many pens did Andy have at first?
- What was the total number of pens that the three boys had in the end?
|
Bobby |
Billy |
Andy |
Total |
Before |
1 u |
3 u + 251 |
6 u |
|
Change |
x 3 |
- 251 |
x 12 |
|
After |
3 u |
3 u |
3 u |
9 u |
(a)
Total number of pens at first
=
1 u + 3 u + 251 + 6 u
= 10 u + 251
10 u + 251 = 38110 u = 381 - 25110 u = 130
1 u = 130 ÷ 10 = 13 Number of pens that Andy had at first
= 3 u ÷
12= 3 u x
21= 6 u = 6 x 13 = 78(b)Total number of pens that the three boys had at the end = 9 u = 9 x 13 = 117 Answer(s): (a) 78; (b) 117