Ben walks 25 miles from home to work. if he walks the first 5 miles in 1 hour, the second 5 miles in 1.4 hours, the third 5 miles in 1.7 hours and the last 5 miles in 1.8 hours, how long will it take him to complete the 25 mile walking distance? (enter numeric value only. if rounding is required, round to the nearest tenth).

The total time taken to complete 25 miles is 7.6 hours.

Solution:

Ben walks 5 miles in 1 hour,

Second 5 miles in 1.4 hours,

Third 5 miles in 1.7 hours,

Last 5 miles in 1.8 hours

So he walked total 20 miles in (1+1.4+1.7+1.8) hours = 5.9 hours = 6 hours (approximately)

So his average speed is miles/hours = 3.33 miles/hours.  

i.e. he travels 3.3 miles in 1 hour,

Then, he travels 1 miles in hours

Hence the total time he will take to walk 25 miles is

That is approximately 7.57 or 7.6 hours.

really really sorry if i'm

-12 -5(x + 4) = 3x

-12 - 5x - 20 = 3x

-12 - 20 - 5x = 3x

-32 - 5x = 3x

    + 5x   + 5x

-32 = 8x

8         8

- 4= x