[formulaspart2][section10]

(1.)  R = 3.50A + 1.50C          use this formula

On Wednesday, total receipts at the Trylon Theater

amounted to \$623 and 151 adult tickets were sold.  How many

children's tickets were sold?

R = 3.50A + 1.50C          use this formula

623 = 3.50(151) + 1.50C   replace R and A with 623 & 151

623 = 528.50 + 1.50C       multiply

-528.50  -528.50        subtract this from each side
________________________
94.5 =          1.50C          subtract
_______          ______
1.50             1.50           divide each side by 1.50

63 = C                       divide and cancel

result:  63 children's tickets were sold.

(2.)   R = 3.50A + 1.50C    use this formula

For the Saturday matinee, the Trylon Theater sold 472

children's tickets.   Total receipts were \$1646.  How many

R = 3.50A + 1.50C          use this formula

1646 = 3.50A + 1.50(472)   replace R & C with 1646 & 472

1646 = 3.50A + 708           multiply

-708          -708       subtract 708 from each side
_______________________
938 = 3.50A                subtract
_____  ______
3.50   3.50               divide each side by 3.50

268 = A                     divide and cancel

result:  268 adult tickets were sold

(3.)   The yearly interest, i, in dollars on an investment, p,

earning 14 1/2 % interest is given by the formula i = 0.145p .

What investment will earn 181.25 in interest in 1 year?

i = 0.145p              use this formula

181.25 = 0.145p           replace i with 181.25
_______  ______
0.145    0.145             divide each side by 0.145

p = \$1250                  divide and cancel

result:  p = 1250

(4.)  Use this formula:  M = (1 - P)C

The mortgage, M, on a house is 60,000 and the percent of down

payment is 25 % .  Find the cost of the house.

M = (1 - P)C                use this formula

60,000 = (1 - .25)C    replace M & P with 60,000 & .25

60,000 = .75C              subtract
_______  _____
.75    .75              divide each side by .75

C = 80,000            divide and cancel

result: The cost of the house is \$80,000 .

(5.)  Use this formula:  M = (1 - P)C

The mortgage, M, on a house is \$45,000  and the percent of

down payment is 20 % .  Find the cost of the house.

Use this formula:  M = (1 - P)C

45,000 = (1 - .20)C   replace M and P with 45,000 & .20

45,000 = .80C           subtract
_______ _____
.80    .80             divide each side by .80

56,250 = C              divide and cancel

result:  The cost of the house is \$56,250 .

(6.)   Use this formula:   d = rt

Find the time required for a jet to travel 45 km at a speed

of 900 km/hr.

Use this formula:   d = rt

45 = 900t                replace d with 45
____  ____
900    900                divide each side by 900

.05 = t                  divide and cancel

t = .05(60)               multiply by 60 to change to minutes

t = 3 minutes             multiply

result:  3 minutes

(7.)  Use this formula:  W = 265 + 0.03S

This week, the salesperson's wages were \$460. Find the total

sales.

Use this formula:  W = 265 + 0.03S

460 = 265 + 0.03S            replace w with 460

-265  -265               subtract 265 from each side
______________________
195 =      0.03S            subtract
____      _______
0.03      0.03                divide each side by 0.03

6500 = S                      divide and cancel

result:  The total sales was \$6500 .

(8.)    Use this formula:  W = 265 + 0.03S

What were the salesperson's total sales for a week in which the

total weekly wages were \$403.30?

Use this formula:  W = 265 + 0.03S

403.30 = 265 + 0.03S            replace W with 403.30

-265    -265                subtract 265 from each side
_______________________
138.30 =       0.03S           subtract
_______        _____
0.03           0.03          divide each side by 0.03

4610 = S                   divide and cancel

result:   The total sales were \$4610 .

(9.)  Use this formula:  S = 2(pi)rh + 2(pi)r2

[The surface area of a cylinder.

Find h given S = 105 and r = 3.

Use this formula:  S = 2(pi)rh + 2(pi)r2

105 = 2(pi)(3)h + 2(pi)(3)2     make substitutions

105 = 6(pi)h + 18(pi)       multiply

-18pi        -18pi         subtract 18pi from each side
______________________
105 - 18pi = 6(pi)h                       subtract
____  ____  _______
6pi    6pi    6pi            divide thru by 6pi

(17.5/pi) - 3 = h          divide and cancel

result:  h = (17.5/pi) - 3

(10.)  Use this formula:  A = P(1 + r)t

Find P if A = 6083.26 and r = 4 % and t = 5.

6083.26 = P(1 + .04)5      make substitutions