Iam confused with both a and b on number 11

You add 300 to 300 and get 600. That is for 4minutes and then you add half of 300which is 150 to the total. 750 is the total answer for a.
4*800 =3200m. Thats how far he bikes . He runs 800m in 2mins so you do 800+800+400 =2000 then you add 800 which gets you 2800m total

For part a:

Divide 300 (meters) by 2 (minutes). You'll get 150 (meters), or Joel's distance if he swims for 1 minute. Then you multiply that by five to find Joel's distance if he swims for 5 minutes (150 multiplied by 5). The product will be your answer.

For part b:

Divide 2400 (meters) by 4 (minutes). You'll get 600 (meters), or Joel's distance if he bikes for 1 (minute). Then, you multiply that by 16 to find Joel's distance if he bikes for 16 minutes (600 multiplied by 16). Add that answer to the answer you found in part a and you have the answer for part b.

The answer is all about the number 4