Cole had to solve some Science 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 3 : 7. At the end of the second week, Cole solved another 45 questions and the number of unsolved questions became
14 of the total number of questions. How many questions did Cole need to solve on the third week to complete his assignment?
|
Solved |
Unsolved |
Total |
First week |
3x2 = 6 u |
7x2 = 14 u |
10x2 = 20 u |
Second week |
+ 45 |
- 45 |
|
Third week |
3x5 = 15 u |
1x5 = 5 u |
4x5 = 20 u |
Total number of questions remains same.
LCM of 4 and 10 = 20
Number of questions that Cole solved at the end of the second week
= 15 u - 6 u
= 9 u
9 u = 45
1 u = 45 ÷ 9 = 5
Number of questions that Cole needed to complete on the third week
= 5 u
= 5 x 5
= 25
Answer(s): 25