21. Huixian's mother buys some shares of Company A on Day 0. On Day 7, the share price

of Company A is $4.60. If she sells all her shares

of Company A and buys 2000 shares of

Company B on Day 7, she would receive $7400.

On Day 12, the share price of Company A is

less than that on Day 7. If she sells all her shares

of Company A and buys 5000 shares of

$4.80 and the share price of Company B is $0.50

Company B on day 12, she would have to pay $5800.

Find

(1) the number of shares of Company A Huixian's

mother has,

(ii) the share price of Company B on Day 12.