Hello!
Z= x-u/sd
(a) x = 40
z = 40-25 / 10 = -15/10 = -1.5
(b) x = 27
z = 27-25 / 10 = 2/10 = 0.2
(c) x = 6
z = 6-25 / 10 = -19/10 = -1.9
Hope that helped
Saving 25%= 17.25 is 125% of Original cost
125/100 = x/17.25
2156.25/100 = 100x/100
x=21.5625
Original cost of jeans = $21.56