SOLVE THESE PROBLEMS CORRECTLY TO BE MARKED BRAINLIEST!

1. Sophie wrote a two-digit number on the board. Max wrote the digit 3 to the right of it and got a number that is bigger than the Sophie's number by 372. What number did Sophie write on the board?

2. Some kids went on a bike ride. The ride was six hours long and the kids traveled 54 miles. For part of the ride they biked at a speed of 7 mph and for part of the ride they biked at a speed of 11 mph. For how long did they bike at the first speed, and for how long at the other speed?

3. I left Boston for Washington, DC, at 7:00 am. At first, my speed was 55 mph; then it was 75 mph. I traveled 630 miles in 10 hours. At what time did I begin to drive faster?

Thanks!

Question

contestada

Respuesta :

Аноним Аноним · Answer 1 · 2021-03-14T19:30:11+01:00

Answer: 1= 41

2= 3 hours biking at the other speed.

3= We began to drive at 75 mph at 1:00 p.m

Step-by-step explanation:

3= x/55 + (630 - x)/75 = 10

75x + 55 * (630 - x) = 41,250 (4,125 as Lowest common multiple)

75x + 34,650 - 55x = 41,250

20x = 41,250 - 34,650 (Subtracting 34,650 at both sides)

20x = 6,600

x = 6,600/20

x = 330 ⇒ 630 - x = 300

Time we drove at 55 mph = 330/55 = 6 hours

Time we drove at 75 mph = 300/75 = 4 hours

We began to drive at 75 mph at 1:00 p.m. (7 am + 6 hours)

hope this helps :)