To solve this type of question we should use the Venn diagram
Let me draw it and show you where we will put each number given
Since there are 15 accidents involved alcohol and excessive speed
Then we should put 15 in the common part of the 2 circles
Since there are 27 accidents involved alcohol
That means 27 = alcohol only + alcohol and excessive speed
Then to find alcohol only we should subtract 15 from 27 to get the number of alcohol only
27 - 15 = 12
Since there are 13 accidents involved excessive speed but not alcohol
That means the excessive speed only is 13
Let us put it in the Venn diagram
Since there are 22 accidents involved neither alcohol nor excessive speed
That means we will put this number outside the circles inside the rectangle
To find the total number of accidents we will add all the numbers in the figure
Then there are 62 accidents in this investigated