How many fewer minutes does it take to drive 35 miles at 30 MPH than to drive the same distance at 25 mph

1 answer:

3 0

To drive 35 miles at 30 mph takes (35/30) hour.
To drive 35 miles at 25 mph takes (35/25) hour.

The difference is (35/25) minus (35/30).

In order to add or subtract fractions, they need a common denominator.
The smallest one available for this situation is 150 .

(35/25) = 210/150
(35/30) = 175/150

Now we can subtract: (210/150) - (175/150) = 35/150 of an hour.
(35/150 hour) x (60 min/hr) = (35 x 60) / (150) min = 14 minutes.

==> It's beginning to look like the answer is NOT 40minutes.
Let's do it again, with a less-elegant but more-intuitive approach:

Time to drive 35 miles at 30 mph = 35/30 = 1-1/6 hours = 70 minutes.
Time to drive 35 miles at 25 mph = 35/25 = 1.4 hours = 84 minutes.

<span>Time saved by driving at 30 mph instead of 25 mph = (84 - 70) = 14 minutes. </span>

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In this figure

alina1380 [7]

Answer:

∠y = 62.5°

∠x = 27.5°

Step-by-step explanation:

z is right angle. ∠z = 90°

∠x = ∠y - 35

∠x + ∠y + ∠z = 180 {Angle sum property of triangle}

y - 35 + y + 90 = 180

y + y - 35 + 90 = 180 {Combine like terms}