Damien played golf on each of the four days of his vacation. His scores on the first three days were 93,92, and 89, and his average for the four days was 90. What was his score on the fourth day?
Because his average for the four days was 90, that means his total score was 90 * 4 = 360, since average is defined in this context as:
(total score) / days played, which is
(total score) / 4 in this context
That means to get the total score, just multiply his average by 4, and we get 360 total score.
We already know his scores on the first 3 days, which were 93, 92, and 89 respectively.
To get his score on the 4th day, we just have to add these up and subtract the sum from the total score, 360
We then get:
360-(93+92+89) = 360 - 274 = a score of 86 on the fourth day
Because his average for the four days was 90, that means his total score was 90 * 4 = 360, since average is defined in this context as:
(total score) / days played, which is
(total score) / 4 in this context
That means to get the total score, just multiply his average by 4, and we get 360 total score.
We already know his scores on the first 3 days, which were 93, 92, and 89 respectively.
To get his score on the 4th day, we just have to add these up and subtract the sum from the total score, 360
We then get:
360-(93+92+89) = 360 - 274 = a score of 86 on the fourth day