A) 6² and 7² , 36 and 49 not this one
B) 7²=49 and 8²=64 not this one
C) 8²=64 and 9²=81 , so 8 and 9, correct answer
(-0.75,0)-(0,3) is the answer
Not sure is this is right but if the chemist wants to make the solution 35% acidic then he can use all of the 30% acid and 5% of the 45% acid.
We have to find LCM of 12,14,16
Refer to the attachment
LCM=2×2×2×2×3×7=16×21=336years