Jack had
38 the number of pens that Oliver had at first. After Oliver gave Jack 108 of his pens, Jack had
34 the number of pens that Oliver had. How many pens did Jack have at first?
|
Jack |
Oliver |
Total |
Before |
3x7 = 21 u |
8x7 = 56 u |
11x7 = 77 u |
Change |
+ 12 u |
- 12 u |
|
After |
3x11 = 33 u |
4x11 = 44 u |
7x11 = 77 u |
The total number of pens that Jack and Oliver had at first and in the end remains unchanged. Make the total number of pens the same. LCM of 11 and 7 is 77.
Number of pens that Oliver gave Jack
= 33 u - 21 u
= 12 u
12 u = 108
1 u = 108 ÷ 12 = 9
Number of pens that Jack had at first
= 21 u
= 21 x 9
= 189
Answer(s): 189