Which is a better buy in the long run-a 60cents light bulb that lasts for 1000 hours or an 89cents bulb that last for 2000 hours?

Well, the 89c bulb lasts twice as much, but costs less than twice as much. So, it's a better option. Here are two other ways to figure this out:

1) After 2000 hours, you will have used two 60c bulbs (each of them lasted 1000 hours). So, you will have spend 1.2 dollars. On the other hand, in the same 2000 hours, you would have needed only one 89c buls (which would have lasted the whole 2000 hours).

2) You can compute the dollars-per-hour ratio: spending 60c for 1000 hours means that you pay

dollars per hour. Similarly, the other bulb costs

dollars per hour, which is less.

option a, c,d are correct.

step-by-step explanation:

from the given figure, it is given that z is equidistant from the sides of the triangle rst, then from triangle tzb and triangle szb, we have

tz=sz(given)

bz=zb(common)

therefore, by rhs rule,δtzb ≅δszb

by cpctc, sz≅tz

also, from δctz and δasz,

tz=sz(given)

∠tcz=∠saz(90°)

by rhs rule, δctz ≅ δasz, therefore by cpctc, ∠ctz≅∠asz

also,from δasz and δzsb,

zs=sz(common)

∠zbs=∠saz=90°

by rhs rule, δasz ≅δzsb, therefore, by cpctc, ∠asz≅∠zsb

hence, option a, c,d are correct.

ruth is 6 years old

step-by-step explanation:

6 + 24 = 30,   so 6/30 = .2  

if you do 1/5 it also equals .2, so that is the answer.