The telephone bill of a certain establishment is party fixed and partly varies as the number of calls consumed. When in a certain month 540 calls made the bill is Rs.1800. In another month 620 calls are consumed then the bill becomes Rs.2040. In another month 500 units are consumed due to more holidays. The bill for that month would be : a) Rs.1560 b) Rs.1680 c) 1840 d) Rs.1950 Expl : Let the fixed amount be Rs. X and the cost of each unit be Rs. Y. Then, 540y + x = 1800 …. And 620y + x = 2040 On subtracting (i) from (ii), we get 80y = 240 -> y = 3 Putting y = 3 in (i) we get : 540 * 3 + x = 1800 x = (1800-1620) = 180 . : Fixed charges = Rs.180, Charge per unit = Rs.3. Total charges for consuming 500 units = 180 +(500*3) = Rs.1680
If A : B = 4 : 7 and B : C = 5 : 9 then A : B : C is : a) 20 : 35 : 63 b) 35 : 36 : 63 c) 30 : 35 : 65 d)25 :34: 68 . Expl : A : B = 4 : 7 B : C = 5 :9 = 5*7/5 : 9 *7/5 = 7 : 63/5 A : B : C = 4 : 7 : 63/5 = 20 : 35 : 63
If 96 is divided into four parts proportional to 5, 7, 4, 8 then the smallest part is : a) 16 b)14 c)20 d) 18 Expl : Given ratio = 5 : 7 : 4 : 8 , sum of ratio = 24 :. The smallest part = (96 *4/24) = 16
Larger number = (23 x 14) = 322.
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