# algebra 1A

at the local per store, zebra fish cost \$2.10 each and neon tetras cost \$1.80 each. if marsha bought 13 fish for a total of \$25.80, not including tax, how many of each type of fish did she buy?

a)7 zebra, 6 neon
b)8 zebra, 5 neon
c)6 zebra, 7 neon
d)5 zebra, 8 neon

1. 👍
2. 👎
3. 👁
1. X Zebra fish.
Y Neon fish.

Eq1: X + Y = 13.
Eq2: 2.1X + 1.8y = 25.80
Multiply Eq1 by -2.1:
-2.1x - 2.1y = -27.3
2.1x + 1.8y = 25.8
-0.3y = -1.5
Y = -1.5 / -0.3 = 5 = Neon.
X + 5 = 13
X = 8 Zebras.

1. 👍
2. 👎

## Similar Questions

1. ### math/economics in calculus

The average cost of manufacturing a quantity q of a good, is defined to be a(q) = C(q)/q. The average cost per item to produce q items is given by a(q) = 0.01q2 − 0.6q + 13, for q >0. I know that the total cost is

2. ### science

Edwin buys a water bottle, reuses it twice, and then recycles it. Eleanor buys a water bottle, reuses it twelve times, and then throws it away. Which energy cost would apply to Edwin, but not to Eleanor? A). the cost of processing

3. ### Math

Madison is having a party. She went to the store and bought a cake for \$18.50 and 20 balloons. Her total bill was \$63.50. How much did each balloon cost if they all cost the same

4. ### math

An instrument store gives a 10% discount to all students off the original cost of an instrument. During a back to school sale an additional 15% is taken off the discounted price. Julie, a student at the local high school,

1. ### Mathematics

the owner of a video store has determined that the cost C, in dollars, of operating the store is approximately given by C(x)=2x^2-18x+670, where x is the number of videos rented daily. find the lowest cost to the nearest dollar.

2. ### Math

Tetras cost \$3.99 each. You can spend at most \$25. How many tetras can you buy for your aquarium? Can someone explain please?

3. ### MATH

The cost to manufacture a product is proportional to the quantity produced, with a cost of \$270000 dollars per day when 900 items are produced. The cost to store n items is proportional to the square of n, with a daily storage

4. ### Algebra

83. Minimizing Marginal Cost The marginal cost of a product can be thought of as the cost of producing one additional unit of output. For example, if the marginal cost of producing the 50th product is \$6.20, it cost \$6.20 to

1. ### math

An instrument store gives a 10% discount to all students off the original cost of an instrument. During a back to school sale an additional 15% is taken off the discounted price. Julie, a student at the local high school,

2. ### Math "Need Help Asap"!

"Find each percent of markup?" 5.)Store's cos:\$26 selling price:\$39 6.)Store's cost:\$125 selling price:\$168.75 7.)Store's cost:\$75 selling price:\$90 "Find each selling price round to the nearest cent?" 8.)"A Video game costs a

3. ### economics

Question.1 Your aunt is thinking about opening a hardware store. She estimates that it would cost \$500,000 per year to rent the location and buy the stock. In addition, she would have to quit her \$50,000 per year job as an

4. ### Math

At a local music store CDs cost 11.99including tax is the number of CDs purchased proportional to the cost of the CDs