Help! I need to get these questions done before 8:30.

Question

Write a system of equations to model each situation. Solve my any method.
4.You and some friends buy hamburgers and milkshakes for lunch. A hamburger costs $1.50 and a milkshake costs $2.00. The total bill for 12 items is $21.50. How many hamburgers and how many milkshakes did your group buy?
5. A collection of dimes and nickels is worth $0.55 There are 7 coins in all. How many dimes and nickels are there?

Answer 1

i dont know how to do them

Answer 2

Be patient. A math tutor will come on line sooner or later and may be able to help you. Ms. Sue and I can't.

Answer 3

h + m = 12 ----> m = 12=h

1.5h + 2m = 21.50
or 3h + 4m = 43
I would solve these by substitution.

coin problem:
d+n = 7 **
10d + 5n = 55
divide by 5
2d + n = 11 ***

subtract ** from *** , and it comes apart very nicely

Answer 4

so no-ones gonna answer then?

Answer 5

ok

Answer 6

I apologize for the delay.

For question 4, we can set up a system of equations as:

h + m = 12
1.5h + 2m = 21.5

where h represents the number of hamburgers and m represents the number of milkshakes.

We can solve this system using elimination method. First, multiply the first equation by -2 and add it to the second equation:

-2h - 2m = -24
1.5h + 2m = 21.5
--------------
-0.5h = -2.5

Solving for h, we get:

h = 5

Substitute h = 5 into the first equation to solve for m:

5 + m = 12
m = 7

Therefore, the group bought 5 hamburgers and 7 milkshakes.

For question 5, we can set up a system of equations as:

d + n = 7
0.1d + 0.05n = 0.55

where d represents the number of dimes and n represents the number of nickels.

We can solve this system using substitution method. Solve the first equation for n:

n = 7 - d

Substitute n = 7 - d into the second equation:

0.1d + 0.05(7-d) = 0.55
0.1d + 0.35 - 0.05d = 0.55
0.05d = 0.2
d = 4

Substitute d = 4 into the first equation to solve for n:

4 + n = 7
n = 3

Therefore, there are 4 dimes and 3 nickels.