Let red marbles = X.
The probability is 1 out of 5, written as 1/5
1/5 in terms of red marbles is equal to the number of red marbles divided by 5x, where 5x is the total number of marbles.
1/5 = x/5x
Now you have 5x total marbles, x red and 4x blue.
Add 5 more red and the new probability is:
(x+5)/(5x+5) = 1/3
Simplify:
3x+15 = 5x+5
Now solve for x:
Subtract 3x from both sides:
15 = 2x +5
Subtract 5 from each side:
2x = 10
Divide both sides by 2:
x = 10/2
X = 5
There were originally 5 red marbles.
<u>Answer:</u>

<u>Step-by-step explanation:</u>
We know from the question that the student earned $12.50 <em>per hour</em>.
Using this information, we can say that if the student worked for <em>h </em>hours, they would make a total of 12.50 × <em>h </em>dollars.
We also know that the total money they earned is $2500.75.
∴ Therefore, we can set up the following equation:

From here, if we want to, we can find the number of hours worked by simply making <em>h</em> the subject of the equation and evaluating:
<em>h </em>=<em> </em>
= 200.6 hours
We need to compute the exact number of days of the loan.
Given:
Loan: 1,870
rate: 11%
term: Oct. 5 to Jan 16.
Oct 5-Oct 31: 26 days
Nov: 30 days
Dec: 31 days
Jan 16: 16 days.
total number of days: 103 days.
Interest = Principal * rate * term
Interest = 1870 * 0.11 * 103/365
Interest = 58.05
Given:
Promissory note $5,380
rate 6.2%
term: July 15 to Dec. 28
July 15 - 31 = 16 days
August: 31 days
September: 30 days
October: 31 days:
November: 30 days
December: 28 days
Total number of days is 166 days
Interest = Principal * rate * term
Interest = 5,380 * 0.062 * 166/365
Interest = 151.70
Answer: <span>2x² + x - 2 (the first option)</span>
5% = 0.5
0.5n = 85
Divide by 0.5
0.5n = 85
/0.5 /0.5
n = 170.
The number is 170.