<em>The answer is 25.12 exactly</em>
If you would like to calculate 1/2 * a + (-3 * a) - 3 * b - 0.7 * a, you can do this using the following steps:
1/2 * a + (-3 * a) - 3 * b - 0.7 * a = 0.5 * a - 3 * a - 0.7 * a - 3 * b = - 3.2 * a - 3 * b
The correct result would be - 3.2 * a - 3 * b.
Let's define variables:
s = original speed
s + 12 = faster speed
The time for the half of the route is:
60 / s
The time for the second half of the route is:
60 / (s + 12)
The equation for the time of the trip is:
60 / s + 60 / (s + 12) + 1/6 = 120 / s
Where,
1/6: held up for 10 minutes (in hours).
Rewriting the equation we have:
6s (60) + s (s + 12) = 60 * 6 (s + 12)
360s + s ^ 2 + 12s = 360s + 4320
s ^ 2 + 12s = 4320
s ^ 2 + 12s - 4320 = 0
We factor the equation:
(s + 72) (s-60) = 0
We take the positive root so that the problem makes physical sense.
s = 60 Km / h
Answer:
The original speed of the train before it was held up is:
s = 60 Km / h
Answer:
a = 6
b = 7
Step-by-step explanation:
Since both 36 and 49 are perfect squares, you can find their square roots which are 6 and 7.
To check to see if it is correct, replace the a with 6 and replace the b with 7, then evaluate the exponents.
Step-by-step explanation:
<u>1</u><u> </u>*9^2 + 4
3
<u>1</u><u> </u>* 81 + 4
3
<u>1</u><u> </u>* 85
3
<u>85</u>
3
=28
