PLS HALPPPPP!!!!
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Answer:
4 hours
Step-by-step explanation:
We know the following:
Total amount Randy earned: $667
Pay for first 40 hours: $14.50 per hour
Pay after 40 hours: $21.75 per hour
We need to find the total extra hours:
If the total number of hours worked are, , then:
Total pay received for the first 40 hours:
If out of $667, Randy earns $580 from the first 40 hours, the left over are earned by extra hours.
$667 - $580 = $87 ------- (a)
Total pay received for working after 40 hours:
We know from eq (a) that total pay is 87, hence we can find the number of hours using this.
Randy worked 4 extra hours.
The smallest such number is 1055.
We want to find such that
The moduli are not coprime, so we expand the system as follows in preparation for using the Chinese remainder theorem.
Taking everything together, we end up with the system
Now the moduli are coprime and we can apply the CRT.
We start with
Then taken modulo 2, 3, 5, and 7, all but the first, second, third, or last (respectively) terms will vanish.
Taken modulo 2, we end up with
which means the first term is fine and doesn't require adjustment.
Taken modulo 3, we have
We want a remainder of 2, so we just need to multiply the second term by 2.
Taken modulo 5, we have
We want a remainder of 0, so we can just multiply this term by 0.
Taken modulo 7, we have
We want a remainder of 5, so we multiply by the inverse of 2 modulo 7, then by 5. Since , the inverse of 2 is 4.
So, we have to adjust to
and from the CRT we find
so that the general solution for all integers
.
We want a 4 digit solution, so we want
which gives .