17 Tres hombres, A, B y C, viajaban con sus esposas, a, b y c. Llegaron a un
río que tenían que cruzar. Solo había un
bote y solo dos podían cruzar a la
vez. Como los maridos eran celosos,
ninguna mujer podía quedarse con un
hombre a menos que su marido también
estuviera presente. ¿Cómo cruzaron
el río?

, 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

it's undefined because anything multiplied by 0 is 0. that said, 7 days is 168 hours

for this case we have that by definition, the surface area of a cylinder is given by:

where:

r: it is the radius of the cylinder

h: it is the height of the cylinder

we can also rewrite it as:

where:

la: it's the lateral area

ba: area of the base

option a