Question

Sarah, Lacey, and Mark stuffed envelopes with invitations for parents to an open house.

• Sarah stuffed 10 more envelopes than Lacey.

• Mark stuffed 3 less than twice as many envelopes as Lacey.

• Altogether they stuffed 503 envelopes.

If x represents the number of envelopes that Lacey stuffed, which equation BEST represents this situation?

x+10+2x−3=503

x+10x+3−2x=503

x+x+10+2x−3=503

x+x+10+3−2x=503

Answer 1

Answer: x+x+10+2x−3=503

Explanation:

Let's define 3 variables:

S = # of stuffed envelopes by Sarah.

X = # of stuffed envelopes by Lacey.

M = # of stuffed envelopes by Mark.

S = 10 + X.

M = 2*X - 3.

X + S + M = 503.

Now we can replace the first two equations into the third equation:

X + (10 + X) + (2*X - 3) = 503.

Then the correct option is: x+x+10+2x−3=503

Now we can also solve the equation, just because it is fun:

X + 10 + X + 2*X - 3 = 503

4*X + 7 = 503

4*X = 503 - 7 = 496

X = 496/4 = 124

Lacey stuffed 124 envelopes.