<span>This is a simple subtraction question. To find the answer, you simple need to subtract 15 from 104. This equals 89, so there were 89 4th graders at school that day in total. In the instance you're unsure that a subtraction equation is right, you can also add your answers back together to double check, so 89 + 15 = 104.</span>
ANSWER

EXPLANATION
The given expression is;

We factor to obtain;

Multiply by the reciprocal of the second fraction

Cancel out common factors to get,


1 mile at 12 m/h is .2 m/min
1 mile at .2 m/min (1/.2) = 5 min So the first mile took 5 minutes
To find how fast the second mile was:
You know it was 1 mile and it took 10 minutes
1/10=.1 m/min which is 6 m/h
The average speed is 6+12/2=9 m/h
Hope that helps. Feel free to ask any questions.