The work of a student to solve a set of equations is shown:

equation a: y = 15 – 2z
equation b: 2y = 3 – 4z

step 1: –2(y) = –2(15 – 2z) [equation a is multiplied by –2.]
2y = 3 – 4z [equation b]
step 2: –2y = 15 – 2z [equation a in step 1 is simplified.]
2y = 3 – 4z [equation b]
step 3: 0 = 18 – 6z [equations in step 2 are added.]
step 4: 6z = 18
step 5: z = 3
in which step did the student first make an error?

step1
step 2
step 3
step 4

1     sepan

2     encuentren

3     tenga

4     hable

5   parezca

6   llegue

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.