Multiply both sides of the second equation by 100 to get rid of the decimals:
0.05<em>n</em> + 0.10<em>d</em> = 1.50
==> 5<em>n</em> + 10<em>d</em> = 150
Multiply both sides of the first equation by -5:
<em>n</em> + <em>d</em> = 21
==> -5<em>n</em> - 5<em>d</em> = -105
Add the two equations together:
(5<em>n</em> + 10<em>d</em>) + (-5<em>n</em> - 5<em>d</em>) = 150 + (-105)
Notice that the terms containing <em>n</em> get eliminated and we can solve for <em>d</em> :
(5<em>n</em> - 5<em>n</em>) + (10<em>d</em> - 5<em>d</em>) = 150 - 105
5<em>d</em> = 45
<em>d</em> = 45/5 = 9
Plug this into either original equation to solve for <em>n</em>. Doing this with the first equation is easiest:
<em>n</em> + 9 = 21
<em>n</em> = 21 - 9 = 12
So Donna used 12 nickels and 9 dimes.
Answer:
30 km
Step-by-step explanation:
1 kilometer = 100 meters.
1 meter = 100 cm
therefore, 1 km = 10,000
and then, 300000 cm is 30 km
Answer:
4.32
Step-by-step explanation:
You can multiply 16 by 0.27 to get the answer.
16*0.27=4.32
You can check your work with estimation because 27% is about 1/4 of the number, and just by looking at the number, 4 is 1/4 of the number.
Answer:
the dryer costs $425
Step-by-step explanation:
x = washer
y = dryer
x + y = 803
x = y - 47
using the second equation a substitute in the first equation we get
y - 47 + y = 803
2y = 850
y = $425
FYI
x = y - 47 = 425 - 47 = $378
Answer:
i believe its C
Step-by-step explanation:
