A contractor is preparing a bid to install swimming pools at a new housing addition. The estimated time to build the first pool is $28$ hours. The contractor estimates an $85$ percent learning rate.

Part $2$

a$.$ How long do you estimate the time required to install the second$$ pool?

$$

$23\mathrm{.}80$ hours. $($Enter your response rounded to two decimal$$ places.$)$

Part $3$

b$.$ How long do you estimate the time required to install the fourth$$ pool?

$$

enter your response here hours. $($Enter your response rounded to two decimal$$ places.$)$