The numbers on Sam's three raffle tickets are consecutive integers. The sum of the numbers is 126. What are the numbers?
x + (x-1) + (x-2) = 126 x, plus the number before x, plus the number behind that is what i have written
3x - 3 = 126 simplified down can you solve from here?
im confused
well, you want three consecutive numbers that add up to 126, yes?
yes
so we have 3 consecutive numbers = 126
how do we write "3 consecutive numbers" with math? well, there are a couple different ways, but i chose: x + (x-1) + (x-2)
x, some random number, plus the number before x, plus the number before that
for instance, if x = 5, then we have x + (x-1) + (x-2) 5 + 4 + 3 3 consecutive numbers does it make sense why i did that now?
and do you have to guess any number tht will sum up to 126?
no, here's where the clever bit comes in: re-write "3 consecutive numbers = 126" as x + (x-1) + (x-2) = 126
consecutive numbers, meaning one is bigger than another by 1 3, 4, 5 17 , 18 , 19 and so on so, if a number is "whatever" whatever, whatever + 1, (whatever + 1)+1
now you can solve for x, and find your 3 consecutive numbers
so would the number that i will plug in be 3 5 and 4?
no, okay let's look at it step-by-step: x + (x - 1) + (x-2) how can we simplify this? what is the first step to collect all the terms?
we want to add all the x's together, and add everything that isn't an x together
you'd get 3 numbers that add up to 126, we dunno which they're, we do know that whatever, whatever + 1, (whatever + 1)+1 = 126
but how if there aren't any other numbers, or do we start with the brackets first?
well, it can be re-written like this x + x - 1 + x - 2 = 126 i just wrote it with () to make it clearer. do you know how to simplify that down now?
ok one sec
there would be only 1 set of 3 that'd add up to that
i got 3x-3
right, remember it's equal to 126 though 3x - 3 = 126 can you solve for x now?
yes one sec
is it x=41
almost, you subtracted 3 instead of adding it though 3x - 3 = 126 3x - 3 + 3 = 126 + 3 3x = 129 x = 43
okay, if x = 43, do you know how you would find the other 2 side lengths now?
ooo my mistake lemme do it again
kk got 43 now you said how would i find the other 2 side lengths right?
yep, do you think you can do it? remember, we know now that x = 43. 43 is one of the three numbers you need remember we wrote the other two as (x - 1) and (x-2)
or, look at it another way: either 43 + 44 + 45 is equal to 126, or 41 + 42 + 43 is cause that's the only trio of numbers you can have
and do u guess the other 2 numbers?
noo, remember we had x + (x - 1) + (x - 2) = 126? well, we know x is 43 now, right? so plug x back in and see what the other 2 numbers are
aka write it as 43 + (43 - 1) + (43 - 2) = 126 the 3 numbers should equal 126
oh we plug in 43 in back right ?
yep
basically: 1. create an equation with a variable 2. solve for the variable 3. use the now-solved variable to find what you need
kk one sec
kk got it thanks soo much :)
Join our real-time social learning platform and learn together with your friends!