Let 't' represent the time of the walk in minutes.
5.1*t = 220
t = 43.14 min
The person needs to walk at least 43.14 minutes to but at least 220 calories.
You have two unknown rates, so we need to develop two equations to solve for these unknowns (based on the information given on the problem statement):
5x + 10y = 725
x + y = 100
By substitution, we get:
5x + 10(100 - x) = 725
5x + 1000 - 10x = 725
-5x = 725 - 1000
-5x = -275
x = -275/-5 = 55
100 - 55 = 45
Thus:
The mechanic who worked for 5 hours charged his time at $55/hr, and the mechanic who worked for 10 hours charged his time at $45/hr.
To verify, plug and chug the results back into the original equations:
5(55) + 10(45) = 725
275 + 450 = 725
725 = 725 [OK]
55 + 45 = 100 [OK]
Hello!
For every 1 blue marble there are 5 greens
You add the numbers in the ratio
1 + 5 = 6
Divide this number from the amount of marbles
60 / 6 = 10
Multiply the ratio by this
1 * 10 = 10
5 * 10 = 50
There are 10 blue marbles and 50 green ones
The answer is 10
Hope this helps!