A teacher has fewer than 200 sweets. She wants to give each pupil in her class an equal number of sweets. If she gives each pupil 2 sweets, she will have 70 sweets left over; if she gives 4 each, she will need 10 more sweets. How many pupils are there in the class? How many sweets does the teacher have?

Answer 1

number of sweets --- s , where s < 200
number of students -- x

case1 : 2x + 70=s
case2 : 4x - 10 = s

4x - 10 = 2x+70
2x = 80
x = 40

then s = 80+70 = 150
( or x = 4x-10 = 150)

There are 150 sweets and 40 students