[快呀] 2條F1 maths

1.
Assume small number is X, the large number is X + 2,
then:
3X - 2(X + 2) = 22
3X - 2X - 4 = 22
X - 4 = 22
X = 26
the small number is 26, and the large number is 28

2. Jacky is y year., assume son is x years and daughter is z years.
y = 2x + 1, then x = ( y - 1 ) / 2
y = 3 z + 2, then z = (y - 2 ) / 3
then
y + x + z = 98 - y
2y + x + z = 98
2 y +(y -1) / 2 + (y - 2) / 3 = 98
12y + 3 y - 3 + 2y - 4 = 588
17y = 595
y = 35#

x = ( 35 - 1 ) / 2
x = 17#

z = ( 35 - 2 ) / 3
z = 11#
Jacky is 35 years old, son is 17 years old, daughter is 11 years old.

1) Let x be the smaller number, then x+2 is the larger number
therefore -> 3(x+2)-2x = 22
3x+6 -2x=22
x=16
therefore-> smaller number is 16, larger is 18

2) because -> jacky = y
therefore -> son = (y-1)/2
daugther = (y-2)/3

y+(y-1)/2 + (y-2)/3 = 98-y
y+y/2+y/3+y = 98+1/2+2/3
y+5/6y = 99+1/6
y = 54+1/11

therefore-> jacky = 54 and 1/11
son -> 26 and 6/11
daughter -> 17 and 4/11