John M. answered • 01/28/18

Tutor

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High School and College Science Tutor

To find the average you just add the numbers and divide by the amount of numbers you added up.

**(292 + 305 + 415 + x)/4 = 343**

**(1012 + x)/4 = 343**

Now multiply both sides by 4.

**4(1012 + x)/4 = 4(343)**

**1012 + x = 1372**

Now subtract 1012 from both sides.

**1012 + x - 1012 = 1372 - 1012**

**x = 360**