Question

if the speed of 3 cars is in the ratio 3:4:5,then the ratio of time taken by these cars to travel the same distance is 20:15:12 ?true or false

Answer 1

It's pretty simple,

The question says the cars travelled the same distance, Which means the product of Speed and Time must be equal,

Because,
Distance = Speed * Time,

Let the common divisor of speeds be x,
=> The speeds of the cars are 3x, 4x, 5x,

Let common divisor of time be y,
=> Time taken by the cars are 20y, 15y, 12y

Now let's find the product !
Distance traveled by the first car = 3x*20y = 60xy,

Distance traveled by second car = 4x*15y = 60xy,

Distance traveled by third car = 5x*12y = 60xy,

We can observe that Distance travelled is same and what the question told was correct,

So by this we can definitely say that the ratio of time taken by the cars is definitely 20:15:12,

Hope you understand, Have a great day !!