Can you please help me with this question? I'm confused.

Question

Mindy’s average monthly salary for the first four months she worked was $300. What must be her average monthly salary for each of the next 8 months so that her average monthly salary for the year is $350?

This are the answer choices.

(A) $400 (B) $380 (C) $390 (D) $375 (E) $370

Answer 1

First find the total for the first 4 months.

$300 x 4 = $1200

Find the total she wants to get for the year $350 x 12 = $4200

The difference is 4200-1200 = 3000

She needs to get the total amount of $3000 in the next 8 months.

Average salary for the next 8 months = 3000/8

(D) $375

Answer 2

weighted average = 4 months * 300 + 8 months * x

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12 months

350 = (4 * 300 + 8 * x) / 12

12 * 350 = 4 * 300 + 8 * x

4200 = 1200 + 8 * x

3000 = 8 * x

x = 375