Question

A x 4 = E
B ÷ 4 = E
C + 4 = E
D - 4 = E
___________
& A + B + C + D = 100

Challenge
*what is the value of E ?*

Answer 1

A = E/4
B = 4E
C = E-4
D = E+4

A+B+C+D =100
Substitute the values

E/4 + 4E + E-4 + E+4 = 100
E/4 + 6E =100
Taking LCM as 4,
E/4 + 24E/4 = 100
25E/4 =100
E = 400/25
E = 16 _____Ans.

Answer 2

according to the question,
4A = B/4 
⇒ B = 16A                         ...(1)
C + 4= 4A
⇒C= 4A - 4                        ...(2)
C + 4 = D - 4
⇒ D= C + 8= (4A - 4) + 8 = 4A + 4 ...(3)
from (1), (2) and (3) we have,
A + B + C + D = 100
⇒ A + 16A + (4A - 4) + (4A + 4) = 100
⇒ 25A = 100
⇒ A = 100/25 = 4
so, 
     4A = E ⇒ E = 4X4 = 16
∴, E = 16