David was fixing a jigsaw puzzle. By the second day, the number of pieces he fixed was 10% of the number of pieces unfixed. After another 6 days, he fixed another 392 pieces and the number of unfixed pieces he was left with was 20% of the number of pieces fixed. How many pieces were left unfixed?
| |
Fixed |
Unfixed |
Total |
| Before |
1x6 =
6 u |
10x6 =
60 u |
11x6 =
66 u |
| Change |
+ 392 |
- 392 |
|
| After |
5x11 =
55 u |
1x11 =
11 u |
6x11 =
66 u |
10% =
10100 =
110 20% =
10100 =
15 Since this is a jigsaw puzzle, there is no change in the total number of jigsaw pieces. Make the total number of jigsaw pieces the same. LCM of 11 and 6 is 66.
Number of additional pieces of jigsaw puzzle that David fixed
= 55 u - 6 u
= 49 u
49 u = 392
1 u = 392 ÷ 49 = 8
Number of pieces that were left unfixed
= 11 u
= 11 x 8
= 88
Answer(s): 88
