Unit test
it takes andrew 720 seconds to take a shower. he spends an additional 420 seconds eating breakfast.
how many minutes does it take andrew to take a shower and eat breakfast?
minutes
[metric reference sheet]
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19 minutes

Step-by-step explanation:

We should know that:  1 minute = 60 seconds

∵ It takes Andrew 720 seconds to take a shower

   converting to minutes ⇒∴ 720 seconds  = 720/60 = 12 minutes

He spends an additional 420 seconds eating breakfast.

converting to minutes ⇒∴ 420 seconds  = 420/60 = 7 minutes

So, The time taken for a shower and eat breakfast = 12 + 7 = 19 minutes

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for