1. Teacher took exam for English, average for the entire class was 80 marks. If we say that 10% of the students scored 95 marks and 20% scored 90 marks then calcualte average marks of the remaining students of the class.
60
70
75
80
Answer: Option C
Explanation:
Lets assume that total number of students in class is 100 and required average be x. Then from the given statement we can calculate : (10 * 95) + (20 * 90) + (70 * x) = (100 * 80)
=> 70x = 8000 - (950 + 1800) = 5250
=> x = 75.
2. The ratio 5:20 expressed as percent equals to
50 %
125 %
25 %
None of above
Answer: Option C
Explanation:
Actually it means 5 is what percent of 20, which can be calculated as,
(5/20)*100 = 5 * 5 = 25
3. Half of 1 percent written as decimal is
5
0.5
0.05
0.005
Answer: Option D
Explanation:
It will be 1/2(1%) = 1/2(1/100) = 1/200 = 0.005
4. Out of 450 students of a school, 325 play football, 175 play cricket and 50 neither play football nor cricket. How many students play both football and cricket ?
75
100
125
150
Answer: Option B
Explanation:
Students who play cricket, n(A) = 325
Students who play football, n(B) = 175
Total students who play either or both games,
\begin{aligned}
= n(A\cup B) = 450-50 = 400\\
\text{Required Number}, n(A \cap B) \\
= n(A)+n(B)-n(A\cup B) \\
= 325 + 175 - 400 = 100
\end{aligned}
5. If number x is 10% less than another number y and y is 10% more than 125, then find out the value of x