Calculate number of chips to solve bit commitment using hash function
$M = H(R_1 || R_2 || b) || R_1$

You already know $R_1$ and you need to find $R_2$ and $b$.

$R_2$ is 40 bits long and $b$ is 1 bit, so you need on average $2^{41}$ guesses to find $R_2$ and $b$ which will give the hash you want.

You know that each chip can do 10,000 hashes per second, so you need to find out how many chips you'll need to do $2^{41}$ hashes in 5 minutes.

$\dfrac{2^{41}}{300seconds} = 7,330,077,518.51 hashes/second$

Since each chip can peform 10,000 hashes per second, we need

$\dfrac{7,330,077,518.51}{10000} = 733,008$ chips (rounded up)

At \$1000 per chip, that is \$733,008,000