It was an increase of 15%
21x + 28 = 156 - 2
21x = 154 - 28
21x/21 = 126/21
X = 6
RM298
reason: multiply RM4 by 10 to get RM40 and add that to RM258 to get RM298
=
Multiply both sides by 15
6 =
Multiply both sides by c
6c = 30 Divide both sides by 6
c = 5