Answer:
50 nickels, 20 quarters.
Step-by-step explanation:
System of equations (q = # of quarters, n = # of nickels):
<em>q + n = 70, 0.25q + 0.05n = 7.50</em>
the first equation can be changed to q = 70 - n, so we are able to <em>substitute q with 70 - n</em>.
So, it will look like <em>0.25*70 - 0.25n + 0.05n = 7.50</em>. This can be simplified to <em>0.2n = 10</em>, which means that n = 50.
Knowing that we can solve <em>q + 50 = 70</em>, which means that q = 20.
The probability is 1/5 (or if you want it in decimals then it is 0.2) (if you want it in percent then it is 20%)
Hope that helped!!!
Answer:
50j
Step-by-step explanation:
workdone = force x distance
workdone = 20x2.5
50j
