Answer:
4.1 shirts
Step-by-step explanation:
Mean can be found by adding all data points and dividing that by the total amount of data points.
There are 12 students selling shirt, which gives you 12 data points.
So (3+4+8+5+2+5+0+5+3+4+3+7)/12 = 4.083...
Which rounds to 4.1 shirts
First figure out what 851 minutes 473 equals to, which is 378
So both sides of the equation should equal to 378
Plus 470 and 378 together
Which equals to 848
So the answer is eight hundred and forty eight