Answer: First Option is correct.
Step-by-step explanation:
Since we have given that
Number of hours Chance can wash the car = 2 hours
Number of hours Sandy can wash the car = 4 hours
Work done by Chance per hour is given by

Work done by Sandy per hour is given by

Work done by altogether per hour is given by

So, Number of hours they take if they together wash the car is given by

Hence, First Option is correct.
Let n be the number 18=60% of n
18=0.6n
18/0.6=n
30=n
Answer:
i think 1
remember like this: y=mx+b
m is slope
b is y intercept
Let's use the "elimination by addition/subtraction" method to solve this system for x and y.
<span> -8x=72-16y
4x=-92+16y <= Mult. all 3 terms by 2: 8x = - 184 + 32y
Now combine the following, column by column:
</span><span> -8x= 72-16y
</span>8x = - 184 + 32y
-----------------------
0 = -112 + 16y. Solving for y, 16y = 112, and y = 7.
Now subst. 7 for y in either of the original equations and calculate x:
<span>4x=-92+16(7) => 4x = -92 + 112 = 20. Then x = 5.
Solution is 5, -7 (or, better written) (5, - 7).</span>