I don't understand math.

=2 7/12 is needed on sunday

Step-by-step explanation:

Friday + Saturday + Sunday = total time studying

1 1/4 + 2 2/3 + sunday = 6 1/2

Get a common denominator of 12

1/4*3/3 =3/12

2/3 *4/4 =8/12

1/2 *6/6=6/12

1 3/12   + 2 8/12 + sunday = 6 6/12

Combine terms

3 11/12 + sunday = 6 6/12

Subtract 3 11/12 from each side

3 11/12  - 3 11/12 + sunday = 6 6/12 - 3 11/12

sunday =  6 6/12 - 3 11/12

Borrow 1 from 6 in the form of 12/12

sunday =  5 + 12/12+ 6/12 - 3 11/12

            = 5 18/12 - 3 11/12

             =2 7/12

it costs $20 to interview each person for a survey. find the cost to obtain a +- 3% margin of error.

step-by-step explanation:

copy and paste, put it in google