Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
See 1 Answer
Let the total number of students in this class be X.
Since each student will send a letter to every other student, each student will send (X - 1) letters.
The total number of letters send will tally as:
(X) (X - 1) = 870
X^2 - X = 870
X^2 - X - 870 = 0
(X - 30) (X + 29) = 0
X = 30 or X = -29 (Rejected as X cannot be negative)
Hence, there are 30 students in the class. [X^2 is X square]
Since each student will send a letter to every other student, each student will send (X - 1) letters.
The total number of letters send will tally as:
(X) (X - 1) = 870
X^2 - X = 870
X^2 - X - 870 = 0
(X - 30) (X + 29) = 0
X = 30 or X = -29 (Rejected as X cannot be negative)
Hence, there are 30 students in the class. [X^2 is X square]