She underestimated by 60 cents. To get this answer all you need to do is multiply 1 dollar times 12 which is $12 and then multiply $.30 by 12 and that gives you $3.60. Then you add the $12 to the $3.60 and that gives you $15.60 which is 60 cents over the estimation.
To find an average you take the numbers to be averaged and add them together then You take the number and divide it by the number of numbers, in this case 4, and that gives you the average.
on this problem you want to do the opposite. you know the average she wants, an 87, so you multiply it by 4. 87*4=348. then you add the three numbers you have (88,81 and 87) and you get 256.
then you subtract 256 from 348 and you get 92. 92 is your answer to check just add 87+81+88+92=348
348/4=87
87 was the average she wanted.
Hope this helped! good luck :)
The answer is 27/23. The way you listed the answers is confusing so I’m not giving a letter. Because [17+10]/[17+6]= 27/23
You are multiplying 975 by 0.034
33.15