Amy works 6 hours each day making one bracelet each hour. she sells the bracelets for $21 each. yesterday she only worked of a day. how much can amy earn from the bracelets she made yesterday?

which answer gives the correct solution and explains how to check if the answer is reasonable?

a.
solution: $84

explanation: if amy worked the whole day, then she would have made about 6 × $20 or about $120. since amy only worked of 6 hr, or 4 hours, she would make about $80 (4 × $20).

b.
solution: $36

explanation: since amy only worked of the day, she made about 2 × $20 or about $40.

c.
solution: $252

explanation: since amy only worked of the day, she earned about 2 × $20 or about $40. since there are 6 hours in the work day, then amy made about 6 × $40 or about $240.