1. a. The number is 10.
b. The number is 17.
c. The number is 12.
d. The number is 120.
e. The number is 14.
f. The number is 2.
g. The number is 99.
h. The number is 8.
2.
a 
a = 11 
b 
b = 8 
c 
c = 4 
d 
d = 150 
e 
e = 15 
f 
f = 1 
g

g = 7 
h

h = 29 
i

i = 6 
j

j = 99 
k

k = 48 
l

l = 6.5 
m

m = 6 
n

n = 2.5 
3.
a 
a = 8 
b 
b = 13 
c 
c = 16 
d 
d = 7 
e 
e = 8 
f 
f = 1 
g

g = 5 
h

h = 25 
i

i = 4 
j

j = 4 
4.
af + 175 = 300
f = 125
The cost of the freshwater crayfish is $125. bv + 25 = 60
v = 35
The cost of the DVD is $35. cc + 4.5 = 7
c = 2.5
The cost of the ice cream is $2.50. ds + 12 = 28
s = 16
The girl is 16 years old. ec + 1250 = 5200
c = 3950
The car costs $3950. fd + 3.5 + 3.1 = 9.4
d + 6.6 = 9.4
d = 2.8
The drink costs $2.80. g3t + 70 = 250
3t = 180
t = 60
Each squash racket costs $60. ht × 600 = 3000
t = 5
The company has 5 stores.