Question

answer with explanation please​

Answer 1

Answer:

Um I don't understand that language

Step-by-step explanation:

Answer 2

Answer:

15.26 min is answer

Step-by-step explanation:

Ram went on a 10 mile drive. He started with a certain speed after covering each mile, his speed is decreased by 20% for the next mile. If he took 5 minutes to the first 5 mile of the drive, what is the time taken by him to cover the next 5 miles?

Let S denotes Ram’s driving speed (in mph) covering 1st mile.

Hence from above data we get following relation for first 5 miles,

5/60 = 1/S + 1/[S*(1 - 20/100)] + 1/[S*(1 - 20/100)^2] + 1/[S*(1 - 20/100)^3] + 1/[S*(1 - 20/100)^4]

or S/12 = 1 + 5/4 + (5/4)^2 + (5/4)^3 + (5/4)^4 …. (1)

Therefore the time taken by Ram to cover the next 5 miles,

= 1/[S*(1 - 20/100)^5] + 1/[S*(1 - 20/100)^6] + 1/[S*(1 - 20/100)^7] + 1/[S*(1 - 20/100)^8] + 1/[S*(1 - 20/100)^9]

= (1/S)*[(5/4)^5 + (5/4)^6 + (5/4)^7 + (5/4)^8 + (5/4)^9]

= (1/S)*(5/4)^5 * [1 + 5/4 + (5/4)^2 + (5/4)^3 + (5/4)^4]

= (1/S)*(5/4)^5 * (S/12) [from (1)]

= (1/12)*(5/4)^5 (hr) = 60*(1/12)*(5/4)^5 (min) = 15.26 (min) [Ans]