Robin can clean 727272 rooms in 666 days.
How many rooms can Robin clean in 999 days?

1,090,908

Find the half of 727272,then when you find the half,add it to 727272

>727,272÷2=363,636

>727,272+363,636=1,090,908

Step-by-step explanation:

1,090,908

Step-by-step explanation:

727,272 divided by 666=

1,092

999 - 666=

333

1,092 x 333=

363,636

727,272 + 363,636=

1,090,908

y = 2x

step-by-step explanation:

if you divide each number in the sequence, you'll see that they all have a multiple factor of 2. each number in the series, and any other numbers which may continue, will be multiplied by 2. therefore, y is the next number in the sequence, and x is the current one, so, our formula will be y = 2x.