What is f(1)? Please help very confusing

2.30+0.4-0.88+1.33 can u explain the answer to this why the answer is 3.15

The two-way table shows the number of people whose hobbies are reading or solving puzzles and who either ride a motorcycle or don’t ride a motorcycle. among people whose hobby is reading, what is the relative frequency of not riding a motorcycle? express your answer as a decimal, and round it to the nearest hundredth if necessary. enter your answer in the box. reading solving puzzles ride a motorcycle 7 3 don't ride a motorcycle 5 9

The measures of the legs of a right triangle are 15m and 20m . what is the length of the hypotenuse