If signs are different you subtract. So 2.5- -1.25 equals 1.25 and keep the sign of the biggest number
The second one is correct
12 because six people came to the party and you shake their hand
WEEKLY Earning Full time = 40 h x $15 = $600/week
Over time = 3 h 25 min or 3h + 25/60 h
WEEKLY Earning Over time = (3 h)x $30 + (25/60) x $30 = $115
TOTAL WEEKLY INCLUDING OVERTIME: = $715
TOTAL SEMI MONTHLY INCLUDING OVERTIME =$715 X2 = $1,430
BIWEEKLY = SEMI MONTHLY = $1,430
TOTAL MONTHLY INCLUDING OVERTIME =$715 x 4 = $2,860