Kari worked twice as many hours as Chris. She also worked ten less than three times as many hours as Mark. Chris and Mark worked the same number of hours.

Kari = 20 hours

Chris = 10

Mark = 10

Explanation:

K is Kari's hours

C is Chris's hours

Karis = 2 x C = K

Chris = C

Mark = C

3C - 10 = K

Assume C is 10 (since 10 is 1/3 of the hours mentioned)

2 x 10 = 20 so K worked 20 hours

20 is twice as much as 10 (C's hours)

and it's 30 - 10 (10 less than 3 times as many hours as Mark)

step-by-step explanation:

ok so im not 100% sure but you would start by adding 5.1t and 1.9t beacuse they have the same variable. that is 7t.   then add -3.6 + 1.2 which is -2.4

so then keep that as -2.4 + 7t. i apologize if this is incorrect. best luck on your test < 3

i believe the answer is the polygon, heptagon.