Last Problem:
A man decides to buy a nice horse. He pays $60 for it, and he is very content with the strong animal. After a year, the value of the horse has increased to $70 and he decides to sell the horse. But already a few days later he regrets his decision to sell the beautiful horse, and he buys it again. Unfortunately he has to pay $80 to get it back, so he loses $10. After another year of owning the horse, he finally decides to sell the horse for $90.
What is the overall profit the man makes?
Answer:
Consider the trade-story as if it describes two separate trades, where: In the first trade, the man buys something for $60 and sells it again for $70, so he makes a profit of $10. In the second trade, the man buys something for $80 and sells it again for $90, so he makes again a profit of $10.
You can also look at the problem as follows:
The total expenses are $60 + $80 = $140 and the total earnings are $70 + $90 = $160.The overall profit is therefore $160 – $140 = $20.
Today’s Problem:
A bus runs at 100 miles per hour at its top speed. It can carry a maximum of 6 persons. If the speed of the bus decreases in a fixed proportion with an increase in number of persons, determine the speed of the bus when the bus has three passengers.