In the expression xy 2, the values of both variables to go through three quality checks, each conducted x and y are decreased by 20%. By this, the value of after a specific part of the processing on the raw the expression is decreased by (C.P.O., 2007) material is completed. Only parts that are not rejected at one stage are put through the subsequent stages
(a)40% 15.20% 8 %
(b)48.8% of production and testing. If average rejection rates 16.21% 9%
(c)51.2% 16.48%
(d)80% at these testing machines during a month are 10%, 265. When water is changed into ice, its volume increases 5% and 2% respectively, then what is the effective by 9%. If ice changes into water, the percentage rejection rate for the whole plant? (M.A.T., 2005) decrease in volume is (R.R.B., 2006) 28 17% 109
Answer
Answer (as printed): B
Explanation
Let X and Y denote the new values of x and y respectively. 4x 4y Then, X = 80% of x = ; Y = 80% of y = . 5 5 2 4x 4y 4 x 16 y 2 64 \ XY 2 = × = × = xy 2 . 5 5 5 25 125 2 64 61 xy 2 = xy 2 . Decrease in the value = xy – 125 125 61xy 2 1 \ Decrease % = × 2 × 100 % = 48.8%. 125 xy
Explanation as extracted from the printed page; notation may be imperfect.