Question

IS 3.

3y-2x
loss
Percentage loss =
X 100%.
selling price
is
Choose the correct answer from the given four alternaives.
In a school, 58% of the total numbers of students are boys. If the
number of girls is 840, how many students are there in the class?
a. 2000
b. 1800
C. 1500
d. 2100
Birr 300 is invested at 6% simple interest per annum. How long will it
take for the interest to amonut Birr 180?
a. 12 years
b. 10 years
c. 8 years
d. 24 years
The decimal form of 672.937% is
a.6.72937
d. 6729.37
b. 67.2937
c. 672.937
9. The simple interest on Birr 400 invested for 4 months was Birr 12.
What is the annual (yearly) rate of interest?
d) 9%
a. 36%
b. 4.8 %
c. 7%​

Answer 1

1. a. 2,000

2. b. 10 years

3. a. 6.72937

4. d. 9%

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%