Charlie had to solve some History questions during a 3-week school holidays. At the end of the first week, the ratio of the number of questions solved to the number of questions unsolved was 2 : 7. At the end of the second week, Charlie solved another 36 questions and the number of unsolved questions became
13 of the total number of questions. How many questions did Charlie need to solve on the third week to complete his assignment?
|
Solved |
Unsolved |
Total |
First week |
2x1 = 2 u |
7x1 = 7 u |
9x1 = 9 u |
Second week |
+ 36 |
- 36 |
|
Third week |
2x3 = 6 u |
1x3 = 3 u |
3x3 = 9 u |
Total number of questions remains same.
LCM of 3 and 9 = 9
Number of questions that Charlie solved at the end of the second week
= 6 u - 2 u
= 4 u
4 u = 36
1 u = 36 ÷ 4 = 9
Number of questions that Charlie needed to complete on the third week
= 3 u
= 3 x 9
= 27
Answer(s): 27