Question

Out of 400 students in the final year in a senior secondary school,300 are offering chemistry.How many students are offering both biology and chemistry if only 70 students are offering neither biology nor chemistry.How many students are offering at least one of biology or chemistry.

Answer 1

400-70 = 330 are offering something
No way to tell how many are doing both. Could be anything from 0-300

Answer 2

Yeah yeah

Answer 3

I)300-x+x+190-x+70=400
490+70-x=400
560-x=400
-x=400-560
-x/-1=-160/-1
x=160

Answer 4

330