Question
When the breadth of a rectangle is reduced by 4cm
(keeping the length constant), its area reduces by 72 cm2 and when the length is reduced by 4cm (keeping the length constant), its area reduces by 64cm2. What is the perimeter of the rectangle? (in cm)Solution
Let the length of the rectangle be l cm and breadth be b cm Area = lb Case 1 - Length = l and Breadth = b - 4 Area = l(b - 4) = lb - 4l So, lb - {lb - 4l} = 72 4l = 72, therefore l = 18 cm Case 2 - Length = (l - 4) and Breadth = b Area = (l - 4)b = lb - 4b So, lb - {lb - 4b} = 64 4b = 64, therefore b = 16 cm Now, Perimeter = 2 (l + b) = 2 (18 + 16) = 2 x 34 = 68 cm
2, 9, 19, 32, 48, 67, ?
64Â Â Â 48Â Â Â 36Â Â Â 22Â Â Â Â 16Â Â Â Â 8
?     190      210      238      274     318
...40 41 86 ? 1084 5445
...148, ‘?’ , 15 4 , 17 8 , 23 8 , 35 8 , 56 8
31   48    67    90   ?      150
22, 23, 31, 57, 122, 247
1. In series II, if ‘x’ is the right term, then find which of the following statement(s) are true.
I. x/124 is a factor 6 and 8.
6Â Â Â Â Â Â Â Â Â Â 5Â Â Â Â Â Â Â Â Â Â 40Â Â Â Â Â Â Â Â Â Â Â 32Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 249Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 240
203, 223, 198, 218, ?, 213
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