Question

The winning relay team in a high school sports competition clocked 48 minutes for a distance of 13.2 km. Its runners A,
B, C and D maintained speeds of 15 kmph, 16 kmph, 17 kmph, and 18 kmph respectively. What is the ratio of the time
taken by B to than taken by D?
(a) 5 : 16
(b) 5 : 17
(c) 9 : 8
(d) 8 : 9

Answer 1

Answer

Option (c)

The ratio of the time taken by B to than taken by D

B : D = 9: 8

Explanation

Here we use the equation

Time= Distance / Speed

The winning relay team in a high school sports competition clocked 48 minutes for a distance of 13.2 km.

Therefore total distance =13.2

Its runners A,B, C and D maintained speeds of 15 kmph, 16 kmph, 17 kmph, and 18 kmph respectively.

There are 4 runners, each of them take equal distance.

Therefore each runner take 13.2/4 = 3.3 km

Speed of B is 16 kmph and speed of D is 18 kmph

Time taken by B to complete distance 3.3 km is   3.3/16

Time taken by C to complete distance 3.3 km is   3.3/18

the ratio of the time taken by B to than taken by D

B : D = 3.3/16 : 3.3/18= 9: 8

Answer 2

Given:

Time = 48 minutes

Distance = 13.2 km

Speed,

Runner A = 15 km / hr

Runner B = 16 km / hr

Runner C = 17 km / hr

Runner D = 18 km / hr

To find:

The ratio of the time  taken by B to that of the time taken by D

Solution:

By formula,

Time= Distance / Speed

Here,

Distance = 13.3 / 4

Hence,

Distance = 3.325

Time taken by B to complete his 3.325 km,

Time taken ( B ) = 3.325 / 16

Time taken ( B ) = 0.207

Time taken by D to complete his 3.325 km,

Time taken ( D ) = 3.325 / 18

Time taken ( D ) = 0.184

To find the ratio of the time taken by B to than that of the time taken by D,

B : D

0.207 : 0.184

9 : 8

Hence, ( c ) 9 : 8 is the answer.