9514 1404 393
Answer:
20 minutes
Step-by-step explanation:
The trains are separating at the rate of 80 +70 = 150 km/hour. The time required to be 50 km apart is then ...
time = distance/speed = (50 km)/(150 km/h) = 1/3 h = 20 minutes
If you have a calculator:
<span>1) To find 1%, divide by 100 (70 / 100 = 0.7) </span>
<span>2) Then, multiply by the % you need (0.7 x 13 = 9.1) </span>
<span>Therefore 70 - 9.1 = 60.9 </span>
<span>If you don't have a calculator: </span>
<span>1) Find 50%, 10%, 5%, and 1%. With these, you can make any % you need. </span>
<span>50% = X / 2 (= 35) </span>
<span>10% = X / 10 (= 7) </span>
<span>5% = first, do 10%, then divide that by 2 (= 3.5) </span>
<span>1% = X / 100 (= 0.7) </span>
<span>Where X is the number you want to work out % for </span>
<span>2) Add those % up to get the amount you want </span>
<span>10% + 1% + 1% +1% = 13% </span>
<span>7 + 0.7 + 0.7 + 0.7 = 9.1 </span>
<span>Therefore 70 - 9.1 = 60.9
Hope that helps :)</span>
