Well she charged twice as much to walk large then small. Let s be small and l be large.
We we know that
l = 2s
we also know that she wants to make 100 so
xl + ys = 100
Where where x is number of large and y is number of small. it says she walked 10 small and 5 large so
5l + 10s = 100
substitute 2s for l because they are same value as shown in first equation I made
5 (2s) + 10s = 100
10s + 10s = 100
20s = 100
s = 5
we can now solve for l
l = 2s
l = 2 * 5
l = 10
So s is 5 and l is 10.
Which one do you need help with?
So, h(t) is how far is Daniel's head from the surface of the water, namely the surface itself is when the height is nill, so his head is at the surface and the height of it is just 0, thus h(t) = 0. Namely, what is "t" when h(t) is 0?

clearly the seconds cannot be a negative unit, so is not -3/2.
If I remember correctly I’m pretty sure you need to subtract