1.For a three-digit number, the sum of the hundreds digit and the units digit is 17. When these two digits are interchanged, the value of the number increase by 99. If the tens digit is 1, find the number.
2.The sum of two numbers is 36. The larger numberis 3 times of the smaller one. Find the two number.
i want step, if have detail step i will choose it for the best answer!!
F.2 maths Applications Of Simultaneous Linear Equation.
2008-02-22 2:48 am
回答 (3)
2008-02-22 3:31 am
✔ 最佳答案
1. let abc be the three-digit number,since the tens digit is 1, b = 1 and the number is a1c
the sum of the hundreds digit and the units digit is 17
a + c = 17.......(1)
when these two digits are interchanged, the value of the number increase by 99
100a +10 + c = 100c +10 +a +99
99a = 99c +99
a=c + 1........(2)
(1) + (2)
2a=18
a=9
c=9-1=8
the number is 918
2. let the smaller number be x, the larger number is 3x
x +3x = 36
4x = 36
x= 9
3x= 27
therefore the smaller is 9 and the larger number is 27
2008-03-01 2:58 am
NO
2008-02-23 4:44 am
1.
Let abc be the three-digit number,then the sum of the hundreds digit and the units digit is 17
a + c = 17 (1)
a = c + 1 (2)
From(2),a - c = 1 (3)
(1) + (3)
2a=18
a=9
Sub.(a=9) into (2)
9 - c = 1
c = 8
2.
Let the smaller number be x, the larger number is 3x
x+3x = 36
4x = 36
x= 9
the larger number is:
=3 X 9
=27
∴the smaller is 9 , the larger number is 27
Let abc be the three-digit number,then the sum of the hundreds digit and the units digit is 17
a + c = 17 (1)
a = c + 1 (2)
From(2),a - c = 1 (3)
(1) + (3)
2a=18
a=9
Sub.(a=9) into (2)
9 - c = 1
c = 8
2.
Let the smaller number be x, the larger number is 3x
x+3x = 36
4x = 36
x= 9
the larger number is:
=3 X 9
=27
∴the smaller is 9 , the larger number is 27
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