Percentage Problems and Solutions

• 15. Evaluate 28% of 450 + 45% of 280

  1. 232
  2. 242
  3. 252
  4. 262

  Answer :

  Option C

  Explanation:

  = (28/100) * 450 + (45/100) * 280
  = 126 + 126 = 252

• 16. If 15% of 40 is greater than 25% of a number by 2, the number is

  1. 14
  2. 16
  3. 18
  4. 20

  Answer :

  Option B

  Explanation:

  15/100 * 40 - 25/100 * x = 2 or x/4 = 4 so x = 16

• 17. The ratio 5:20 expressed as percent equals to

  1. 50 %
  2. 125 %
  3. 25 %
  4. 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

• 18. A batsman scored 120 runs which included 3 boundaries and 8 sixes. What percent of his total score did he make by running between the wickets.

  1. 40%
  2. 50%
  3. 60%
  4. 70%

  Answer :

  Option B

  Explanation:

  Number of runs made by running = 110 - (3 x 4 + 8 x 6)
  = 120 - (60)
  = 60
  
  Now, we need to calculate 60 is what percent of 120.
  
  => 60/120 * 100 = 50 %

• 19. 1/2 is what percent of 1/3

  1. 150%
  2. 200%
  3. 250%
  4. 300%

  Answer :

  Option A

  Explanation:

  1/2/1/3 * 100 = 1/2 * 3/1 * 100 = 150 %

• 20. In expressing a length of 81.472 km as nearly as possible with the three significant digits, find the percentage error

  1. 0.35%
  2. 0.34%
  3. 0.034%
  4. 0.035%

  Answer :

  Option C

  Explanation:

  Error = (81.5 - 81.472) = 0.028
  Required percentage = \begin{aligned}
  \frac{0.028}{81.472} \times 100 = 0.034 %
  \end{aligned}

• 21. In a hotel, 60% had vegetarian lunch while 30% had non-vegetarian lunch and 15% had both type of lunch. If 96 people were present, how many did not eat either type of lunch ?

  1. 27
  2. 26
  3. 25
  4. 24

  Answer :

  Option D

  Explanation:

  \begin{aligned}
  n(A) = \left(\frac{60}{100}*96\right) = \frac{288}{5} \\
  n(B) = \left(\frac{30}{100}*96\right) = \frac{144}{5} \\
  n(A\cap B) = \left(\frac{15}{100}*96\right) = \frac{72}{5} \\
  \text{People who have either or both lunch} \\
  n(A\cup B) = \frac{288}{5}+\frac{144}{5}-\frac{72}{5} \\
  = \frac{360}{5} = 72
  \end{aligned}
  
  So People who do no have either lunch were = 96 -72
  = 24