There's a pretty simple formula to follow: count of multiples [tex]*[/tex] average of the multiple.
To find the average, we take the smallest multiple of 4 which is in the range of 1 and 150 which is 4 of course. And the largest would be 148 since that's the only number in the range. So now average them: [tex]\frac{4 + 148}{2} = \frac{152}{2} = 76[/tex]
Now we find the count of the multiples which is in the range of 1 to 150. To do that, we use this formula:
[tex]\frac{\text{largest multiple} - \text{smallest multiple}}{n} \\[/tex]
Here, [tex]n[/tex] is 4 so this would be:
[tex]\frac{148-4}{4} = \frac{144}{4} = 36[/tex]
This would give you the exclusive count of all the numbers, but we want the inclusive count so, we simple add 1 so the count would be [tex]37[/tex]
Now following the 1st formula we get: [tex]37 * 76 = 2812[/tex]
So the answer would be 2812! :D
And here's the check too: