A student has an average of 78 on seven chapter tests. If the student's scores on six of the tests are 76, 74, 76, 80, 83, and 91, what was the score on the remaining test? 80 66 78 79

The score is 66

Step-by-step explanation:

Say the unknown score is x

Average = Total score/no of occurrence

78 = (x + 76 + 74 + 76 + 80 + 83 + 91)/7

78 × 7 = x + 76 + 74 + 76 + 80 + 83 + 91

546 = x + 480

546 - 480 = x

66 = x

∴ x = 66

the multiples of 15 are 15, 30,45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195,   210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 360, 375,   390, 405, 420, 435, 450, 465, 480, 495, 510, 525, 540, 555, 570, 585, 600, 615, 630, 645, 660, 675, 690, 705, 720, and 735.

the factors of 15 are 1, 3, 5, and 15.

hope that , fam!

-une, your fren : )