Quants 8 - Percentage

Key Points to Remember:

By a certain percent, we mean that many hundredths. Thus, x percent means, x hundredths, written as x%.
To express x% as a fraction, we have x% = x/100
To express a/b as a percent, we have a/b = (a/b) * 100%


Practice Questions:

Question 1:

Express as fraction.
(i) 58% (ii) 8% (iii) 0.4% (iv) 0.09%

(i) 58% = 58/100 = 29/50
(ii) 8% = 8/100 = 2/25
(iii) 0.4% = 0.4/100 = 4/1000 = 1/250
(iv) 0.09% = 0.09/100 = 9/10000

Question 2:

Express as decimal.
(i) 7% (ii) 25% (iii) 0.3% (iv) 0.02%

(i) 7% = 7/100 = 0.07
(ii) 25% = 25/100 = 1/4 = 0.4
(iii) 0.3% = 0.3/100 = 3/1000 = 0.003
(iv) 0.02% = 0.02/100 = 0.002%

Question 3:
Express as rate percent.
(i) 23/36 (ii) 6(3/4) (iii) 0.007

(i) 23/36 = 23/36 * 100 = 575/9 = 63(8/9) %
(ii) 6(3/4) = 27/4 = 27/4 * 100 = 675%
(iii) 0.007 = 7/1000 = 0.7%


Question 4:
(i) 28% of 450 + 45% of 280
(ii) 16(2/3) of 600 gram - 33(1/3) of 180 gram

(i)
= (28/100) * 450 + (45/100) * 250
= 126 +126
= 252
(ii)
= (50/3) * (1/100) * 600 - (100/3) * (1/100) * 180
= 100 - 60
= 40 gram


Question 5:

(i) 2 is what percent of 50?
(ii) What % of 7 is 84?
(iii) What % of 2 metric tonnes is 40 quintals?

(i) (2/50) * 100 = 4%
(ii) 84/7 * 100 = 1200%
(iii) 40/(2*10) * 100 = 200%

Time to Think:
(i) 1/2 is what % of 1/3?
(ii) What % of 6.5 litres is 130 ml?