The associative law states that it doesn't matter how we group numbers when we add and/or multiply. So we could rearrange the brackets and parentheses to get the equivalent equation:
9m(6+n)
Both equations total:
54m+9mn
(I applied the distributive property to solve it).
I need the options it gives to answer
I am struggling with this question myself, but the closest answer I am getting is 42. I got this answer by putting the equations in a graph and comparing the lines.
She needs 70 buttons.
13x10=130
200-130=70 done!
Answer:
Rate of the boat in still water 73 mi/hr
Rate of the current 18 mi/hr
Step-by-step explanation:
Calculation to determine the rate of the boat in still water and the rate of the current
Let B represent the speed of the boat in still water.
Let S represent the speed of the stream
Speed upstream = B-S.
Speed downstream = B+S.
Using the equation for distance
Distance=Rate * Time
Upstream
(B-S)7 = 385
(B+S)5= 455
Simplify first:
B-S=385/7
B-S = 55
B+S=455/5
B+S = 91
Solve by elimination. Add the two equations.
2B=55+91
2B = 146
B=146/2
B = 73 mi/hr
Substitute this into either equation and solve for S.
B+S = 91
73+S = 91
S=91-73
S = 18 mi/hr
Therefore the rate of the boat in still water is 73 mi/hr and the rate of the current is 18 mi/hr
