In an examination, 80 students secured
first class marks in English or Maths
Out of these, 50 students obtained
first class Marks in Maths and 10
in English and Maths both. How many
students have secured first class
marks in English only?

Number of students who secured first class in English only is 20

Step-by-step explanation:

Total number of students who secured first class in English or Maths, T = 80

Number of students who secured first class in Maths, M = 50

Number of students who secured first class in both English and Maths, EM = 10

⇒ Let the number of students who secured first class in English only be x.

Total students with first class, T = M + EM + x

⇒ 80 = 50 + 10 + x

⇒ 80 = 60 + x

∴ x = 80 - 60 = 20

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3

      2

  2 is to go somewhat to the top right of a because it is squared    

v= a h/3