NEED HELP AS SOON AS POSSIBLE! GIVING BRAINLIEST BECAUSE I NEED THIS REALLY SOON!!!!!! ~ thanks ~

Answer:
a) The temperature of the water at 5 p.m. would be below 0
b) The temperature of the water at 5 p.m. would be -2.5 *C
Step-by-step explanation:
A) Adding-10.6 and -8.7 would give you over 19, and this would be more than 16.8. Therefore, we can assume that 16.8- 19 is less than zero
B) -10.6+16.8-8.7=-2.5