-0.4x=2.5 divide both sides by -0.4
x=-6.25
Answer:

Step-by-step explanation:
we know that
The simple interest formula is equal to
where
I is the Final Interest Value
P is the Principal amount of money to be invested
r is the rate of interest
t is Number of Time Periods
in this problem we have
substitute in the formula above
solve for r

convert to percentage (multiply by 100)

Answer:

Step-by-step explanation:




Answer:
i would say for the second one 2.5 and the first one about 30
Step-by-step explanation:
Answer:
an additional 60 gallons will be pumped in and a total of 348
Step-by-step explanation: