The sophomore class at MLK High School raised $2591 from the sale of concert tickets. Tickets sold for $3.50 if purchased in advance and $6.00 if purchased at the door. If a total of 631 tickets were sold, how many tickets were sold at the door? Help me Please

There were 153 tickets sold at the door

Step-by-step explanation:

Let a = number of advance tickets

d = number of door tickets

a+d = 631

a*3.50 + d*6 = 2591

Solving the first equation for a

a+d = 631

a = 631 -d

Substituting this into the second equation

a*3.50 + d*6 = 2591

(631 -d) *3.5 +6d = 2591

Distribute

2208.5 -3.5d +6d =2591

Combine terms

2208.5 +2.5d = 2591

subtract 2208.5 from each side

2208.5-2208.5 +2.5d = 2591-2208.5

2.5d = 382.5

Divide by 2.5 on each side

2.5d/2.5 =382.5/2.5

d = 153

There were 153 tickets sold at the door

153 tickets at door

Step-by-step explanation:

A: advance tickets

D: at door

A + D = 631

D = 631 - A

3.5A + 6D = 2591

3.5A + 6(631 - A) = 2591

3.5A + 3785 - 6A = 2591

2.5A = 1195

A = 478

D = 631 - 478 = 153

move it to the other side

step-by-step explanation: