Answer:
1. a. 2,000
2. b. 10 years
3. a. 6.72937
4. d. 9%
Step-by-step explanation:
1. If 58% are boys, the percentage of girls is:
= 100 - 58
= 42%
That means 840 is 42% of the students in class. The students in class are therefore:
= 840 / 42%
= 2,000 students
2. If Birr 300 is invested at 6% per year, the amount in interest it earns per year is:
= 300 * 6%
= Birr 18
To get to Birr 180, it would take:
= 180/18
= 10 years
3. When a number is in percentage that means that it is a fraction with the denominator being 100. The number is decimal will therefore be it divided by 100:
= 672.937/100
= 6.72937
4. The investment accrued Birr 12 out of Birr 400 in 4 months. This means that it increased by:
= 12/400
= 3%
A year can be divided into three by 4 months. This means that the yearly rate is therefore:
= 3% * 3
= 9%
