 |
| ||
| |||
|
| Math Central | Quandaries & Queries |
|
Question from deeqa, a parent: 1. A car traveled 175mi at a certain speed. If the speed had been 20mph faster, 2. The average weekly allowance A of children varies directly as their grade level, G. The time T required to do a job varies inversely as the number of people P working. It takes 2hr for 4 |
Hi Deeqa,
For your first question look at Stephen's response to an earlier question.
The statement that the average weekly allowance A varies directly as the grade G means that there is a constant number k, a number that doesn't change with grade level, so that A = k × G. Since grade 8 students (G = 8) have an average weekly allowance of $8.56 (A = $8.56) you know that
$8.56 = k × 8
and hence
k = $8.56/8 = $1.07
Thus A = $1.07 × G. If G = 5 what is A?
The time T required to do a job varies inversely as the number of people P working means that there is a constant number k so that T = k × 1/P. As I did in the previous problem use the known values to determine k and then apply this value to answer the question.
Penny
| ||
| ||
| ||
 |
 |
|
Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.