Multiple choice

State 'T' for true and 'F' for false and select the correct option. 1. If the area of a rectangle ABCD is 100 cm2 and AB : CD is 2 : 1, then AB = 20 cm and CD = 10 cm. 2. Sam has total 300 red and black balls. If 25% of them are black, then there are 125 red balls. 3. If the speeds of three trucks are in the ratio 3 : 4 : 5, then the ratio of time taken by these trucks to travel the same distance is 20 : 35 : 45.

  1. 1 - F, 2 - T, 3 - T

  2. 1 - T, 2 - T, 3 - T

  3. 1 - F, 2 - F, 3 - F

  4. 1 - T, 2 - F, 3 - F
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

1: Area = 100, AB:CD=2:1. If AB=20, CD=10, Area = 20*10=200 (False). 2: 300 total, 25 percent black = 75, red = 225 (False). 3: Speed ratio 3:4:5, Time ratio 1/3:1/4:1/5 = 20:15:12 (False).

AI explanation

For statement 1, the sides of a rectangle are equal, so if the area is 100 cm2 and the ratio is 2:1, the sides are 20 cm and 5 cm, not 10 cm. For statement 2, 25% of 300 balls is 75 black balls, leaving 225 red balls. For statement 3, when distance is constant, time is inversely proportional to speed, so the ratio of time for speeds in the ratio 3:4:5 is the harmonic mean, yielding a ratio of 20:15:12. All statements are false.

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