I think it’s d because it’s like similar
An exponential behavior can be observed.
Let x be the number of years she has to wait.
100((1+0.08/12)^12x) = 150
Now solve for x.
log base 1.08/12 of 1.5 = 61.02 approx
12x=61.02
x=5.09 years
Let
The origin of coordinates the tree
r1 = vector position of the child 1.
r2 = vector position of the child 2
Child 1:
r1 = (12i + 12j)
Child 2:
r2 = (-18i + 11j)
The scalar product will be given by:
r1.r2 = ((12) * (- 18)) + ((12) * (11)) = - 84
The scalar product of their net displacements from the tree is -84m ^ 2