Acollege student earned $8200 during summer vacation working as a waiter in a restaurant on the boardwalk at the beach. the student invested part of the money at 7% and the rest at 10%. if the student received a total of $664 in interest at the end of the year, how much was invested at 10%

$3000.

Step-by-step explanation:

Suppose the amount invested at 7% is $X and the amount invested at 10% is $Y (assuming that the college student invested all his/her income on the two schemes). Therefore:

X + Y = 8200 (The sum of investments is basically the total income).

0.07X + 0.1Y = 664 (The sum of the interest received from the invested amounts is actually the total return).

Now solving these 2 simultaneous equations:

x + y = 8200 (Equation 1)

7x + 10y = 66400 (Equation 2)

From (Equation 1):

x = 8200 - y (Equation 3)

Put (Equation 3) in (Equation 2):

7(8200 - y) + 10y = 66400.

57400 - 7y + 10y = 66400.

3y = 9000

y = 3000.

$Y is the amount invested at 10%, therefore the final answer is $3000!!!

sas (side angle side)

aa(angle angle)

sss(side side side)

sas you have to find two sides with an angle in between

aa you find two angles because it will always add up to 180

sss find all sides

step-by-step explanation: