Ans: (a) $\$72$ (b) Yes
- The round-down estimate of the total amount
$\begin{array}{cl}
= & 16 + 24 + 32 \\
= & \$72
\end{array}$ - By the result of (a), the round-down estimate of the total amount they have is $\$72$. That means the total amount they have is more than $\$72$. Therefore, they have enough money to buy a football of price $\$70$.
