A photocopier can print 12 copies in 18 seconds. At this rate, how many copies can it print in 42 seconds?​

It should be 28 copies

Step-by-step explanation:

If you divide 42 by 18 it gives you 2.33333333

If you multiply 12 by 2.33333333 it gives you 28

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,