average to be 78. What did he score on his fifth exam?
please explain how you got the answer help!!!
2007-02-20 16:27:45 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
The answer is 76 and i just added all of them and then divided by 4 and then i averaged in 76 too it.
2007-02-20 16:33:24 · answer #1 · answered by Anonymous · 0⤊ 0⤋
78 x 5 = 390
80 + 88 + 71 + 75 = 314
390 - 314 = 76
The answer is 76
2007-02-21 00:36:54 · answer #2 · answered by Anonymous · 0⤊ 0⤋
80 + 88 + 71 + 75 +x = (78)(5) (<--- 5 is the number of tests he did)
x= 390 - 80 - 88 -71 -75
x=76
2007-02-21 01:11:31 · answer #3 · answered by abd 5 · 0⤊ 0⤋
78*5 = 80+88+71+75+x
solve for x
390= 314+ x
-314 = -314
76=x
2007-02-21 00:37:07 · answer #4 · answered by drewbear_99 5 · 0⤊ 0⤋
average of a group of numbers is their sum divided by N(which is the total number of numbers)then here 78=(80+88+71+75+x)/5 then by solving the equation you will have x=76
2007-02-21 00:37:06 · answer #5 · answered by amin s 2 · 0⤊ 0⤋