Answer:
7 9/10 pounds
Step-by-step explanation:
Let the speed for the first 12 mi be x mi/h, the speed for 18 mi was (x+4) mi/h
thus given that
time=distance/speed
the average time will be:
3=(12+18)/(x+x+4)
3=30/(2x+4)
solving for x we get
3(2x+4)=30
6x+6=30
6x=24
x=4 mi/hr
Answer: 12 mi/hr
<h3>
Step-by-step explanation:</h3>
<u>Step</u> <u>Property</u>
2x+6 = 22 given
2x = 16 addition property of equality (-6 added to both sides)
x = 8 multiplication property of equality (both sides × 1/2)
_____
In general equations are solved by reversing the steps done to the variable. Here, the variable (x) is multiplied by 2 and 6 is added to that product. So, to find x, we undo the addition of 6 (by adding -6, the additive inverse), and undo the multiplication by 2 (by multiplying by 1/2, the multiplicative inverse).
If other functions were performed on the variable in the original equation, their inverse functions would be used, too, as part of the solution process.
