Answer:

Step-by-step explanation:
The Simple Interest Equation is 
where
A = Total Accrued Amount (principal + interest)
P = Principal Amount
I = Interest Amount
t = Time Period involved in months or years
In this case, we do not know the values of the equation (A and P), but we know the amount of interest accrued
If we define our principal whit this formula, we are able to know the rest of the values:

clearing

replacing

Solving





Give them the same denominator.
19/30 is what you have left
Answer:
Using the estimate:
The car has to go for 1,200 miles but it consumes a gallon of gasoline for every 30 miles. The number of gallons it will need is therefore:
= 1,200 / 30
= 40 gallons
Each gallon costs $3.00 so the total cost is:
= 40 * 3
= $120
Without using the estimate:
The car has to go for 1,211 miles but it consumes a gallon of gasoline for every 29 miles. The number of gallons it will need is therefore:
= 1,211 / 29
= 41.76 gallons
Each gallon costs $3.40 so the total cost is:
= 41.76 * 3.40
= $141.98
<em>Using the estimate provides a lower cost of gasoline for the trip. </em>
For this problem, let x be the number of children and y for adults. Formulate the equations: 1st equation, x + y = 3,200 and 2nd equation 5x + 9y = 24,000. Re-arrange 1st equation into x = 3200 - y. Then, substitute into 2nd equation, 5(3,200-y) + 9y = 24,000. Then, solve for y. The 16,000 - 5y + 9y = 24000. Final answer is, y = 2000 adults went to watch the movie.