Question

(54+a):2=40
(18+b):3=39
(c+74):4=20
(7+d):5=10

Answer 1

(54 + a) : 2 = 40 
54 + a= 40 x 2 
54 + a = 80 
a = 80 - 54
a = 26

(18 + b) : 3 =39
18 + b = 39 x 3 
18 + b = 117
b = 117 - 18
b = 99

( c + 74) : 4 = 20
c + 74 = 20 x 4
c + 74 = 80 
c = 80 - 74
c = 6

( 7 + d) : 5 =10
7 + d = 10 x 5 
7 + d = 50 
d = 50 - 7
d = 43

Answer 2

1)54:2+a:2=40
27+a:2=40
a:2=40-27
a:2=13
a=13×2
a=26
2)18:3+b:3=39
6+b:3=39
b:3=39-6
b=33×3
b=99
3)c+74=20×4
c=80-74
c=6
4)7+d=50
d=50-7
d=43