Question
A towel was 75 cm broad and 120cm long. When bleached,
it was to have lost 40% of its length and 20% breadth. The percentage of decrease in area is:Solution
Original area = 75 × 120 = 9,000 sq cm. Reduced length = 60% of 75 cm = 45 cm Reduced breadth = 80% of 120 cm = 96 cm Reduced area = 45 × 96 = 4,320 sq cm Reduction in area = 9,000 – 4,320 = 4,680 sq m. ∴ % Reduction = 4,680/(9,000 ) × 100 = 52%. SHORTCUT ALTERNATE METHOD: LET LENGTH OF RECTANGLE = 100 AND BREADTH OF RECTANGLE = 100 SO AREA = L×B = 100×100 = 10000 SO NEW LENGTH OF RECTANGLE = 60 AND BREADTH OF RECTANGLE = 80 SO AREA = L×B = 60×80 = 4800 ∴ % Reduction = (10000-4800)/10000× 100 = 5200/10000× 100 = 52%.
16, 36, 128, 768, 6144, 61440
1286, 1061, 865, 696, 560, 431, 331
9 20 63 255 1285 7716
...16,22,30,45,52,66
48, 73, 109, 154, 222, 303
3 5 9 17 32 65
...- Find the wrong number in the given number series.
25, 36, 50, 68, 92, 120 Find the wrong number in given number series.
6490, 6377, 6294, 6211, 6138
Find the wrong number in the given number series,
121, 130, 116, 139, 103, 148
Find the wrong number in the given number series.
7, 9, 16, 12, 25, 15, 36
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