Question

teacher tells the class that the highest mark obtained by a student in her class is twice the lowest mark plus 7. the highest score is 87. (take the lowest score to be like ).

Answer 1

let the lowest mark =x

2x+7=87
2x=87-7
2x=80
x=80/2
x=40
lower mark is 40

Answer 2

let the lowest marks be x
highest marks=2*x+7
=2x+7
highest score=87
87=2x+7
2x=87-7
2x=80
x=40
so, the lowest score is 40.