In a two-digit number, the units digit is one less than twice the hundreds digit. If the digits are reversed, the new number is 49 more than three times the original number.
What's the original number? I'm working with substitution equations. So I need to have two equations and combine them. Could you also please show your work so that I can really understand it?
2006-09-07 12:24:39 · 7 answers · asked by Sakura X 2 in Education & Reference ➔ Homework Help
Sorry. Typo for hundred. XP
2006-09-07 13:06:48 · update #1
First of all there is no hundreds digit in a two-digit number, only a tens digit and units digit. I will assume that where your problem says hundreds that it is supposed to be tens.
You are going to use the concept that a two digit number, such as 47, can be written 4*10 + 7
So, let t = the tens digit
and u = the units digit
Then 10t + u = the value of the number
and 10u + t = the value of the number when the digits are reversed.
You will have two equations to solve your problem
1) 2t -1 = u
2) 10u + t = 3(10t + u) + 49
I'm sorry, but something is wrong the the problem because this doesn't give an answer that makes sense. Check and see if you made a typing error.
2006-09-07 12:58:04 · answer #1 · answered by LARRY R 4 · 1⤊ 0⤋
u have to multiply the 10's digit by 10, because it is in that position. for example, if u are looking at the number 45, it is
(10 * 4) + 5 = 45
10x + y
so, create ur equations:
y = 2x -1 (y is one less than 2 times the tens digit x)
10y+x = 49 + 3(10x + y) (reversed # is 49 + 3 times the orig #)
simplify this:
10y + x = 49 + 30x + 3y
substitute y = 2x-1 into the 2nd formula:
10(2x-1) + x = 49 + 30x + 3(2x-1)
20x - 10 + x = 49 + 30x + 6x - 3
21x - 10 = 46 + 36x
15x = -56
x = -56/15
ok this is not the right answer.. however i don't know if the info is not correct, or what i am doing is not correct. =T good luck
2006-09-07 19:51:48 · answer #2 · answered by sasmallworld 6 · 0⤊ 0⤋
Dude this is a toughie.
Its nearly 1am so I have probably made a mistake but here goes.
Assume the Tens digit is Q.
The units digit is one less than the tens digit multiplied by 2.
Therefore: Units Digit = (2Q -1)
From this we can work out the original number using Algebra:
The tens digit of the number is Q
Therefore to make the original number we simply do:
Original No. = 10Q [the tens digit multiplied by 10] + (2Q - 1)
= 12Q -1
The new number is the original reversed:
New no. = 10*(2Q - 1) + Q
= 21Q - 10
Now we have two equations, we se how they are related.
Three times the original Number = 3(12Q -1)
= 36Q - 3
New No. = 3*Original No + 40
Therefore:
21Q -10 = 36Q - 3 + 49
-56 = 15Q
BUT IT GETS THE WRONG ANSWER.
So i've made a mistake somewhere.
Sorry.
lol.
2006-09-07 19:54:17 · answer #3 · answered by theoneandonlyhaz 2 · 0⤊ 0⤋
I'm assuming you have to make up your own equations?
As well, in a two digit number there is no 'hundreds' digit. Only tens digit and unit digit.
2006-09-07 19:28:19 · answer #4 · answered by o0twiggles0o 3 · 0⤊ 0⤋
TWO-DIGIT number, UNITS digit is one less than twice the HUNDREDS digit??
Last I knew, there was a UNITS digit and a TENS digit in a TWO-DIGIT number.... No hundreds.
2006-09-07 19:31:03 · answer #5 · answered by hawk22 3 · 0⤊ 0⤋
49 divided by 3 = 14
2006-09-07 19:31:24 · answer #6 · answered by GIR 3 · 0⤊ 1⤋
x
2006-09-07 19:38:05 · answer #7 · answered by Anonymous · 0⤊ 0⤋