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Timothy ran a lemonade stand for 6 days. on the first day he made $5. Each day after that he made $2 more than the previous day. How much money did Marcus make, , after the 6 days?A) $60B) $15C) $12D) $30

Respuesta :

Step `1;

Total number of days = 6

Step 2:

First day = $5

Second day = $5 + $2 = $7

Third day = $7 + $2 = $9

Fourth day + $9 + $2 = $11

Fifth day = $11 + $2 = $13

Sixth day = $13 + $2 = $15

Step 3:

Marcus made = $5 + $7 + $9 + $11 + $13 + $15

= $60

Second method

Use the sum of nth terms of arithmetic progression.

first term a = $5

Common difference = 2

n = 6

[tex]\begin{gathered} S\text{um of the 6 terms = }\frac{n}{2}(\text{ 2a + (n-1)d)} \\ =\text{ }\frac{6}{2}\text{ ( 2}\times5\text{ + (6 -1) }\times\text{ 2)} \\ =\text{ 3( 10 + 5}\times2\text{ )} \\ =\text{ 3( 10 + 10 )} \\ =\text{ 3 }\times\text{ 20} \\ =\text{ \$60} \end{gathered}[/tex]

Final answer

Marcus made = $60 Option A

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