In which step did her first error occur?

Tom and maria typed in words in the ratio of 1 : 5 in 20 minutes. they typed 864 words altogether. find the number of words that each of them typed

Is the square root of 4 plus the square root of 16 rational?

What is the missing statement in step 4? ? rts ? ? vtu and ? rtu ? ? vts ? rts ? ? rvs and ? rtu ? ? stv ? vrs ? ? vru and ? usr ? ? usv ? vur ? ? vus and ? uvs ? ? sru