Page 104 - Maths Skills - 7

102 Maths

MIND MAP

Comparing Quantities

Ratio Proportion
Symbol of ratio is ‘:’ Symbol of proportion is ‘::’
First term or a : b Second term or If two ratio’s are equal then they are in
Antecedent consequent proportion
Ratio i.e. a : b = c : d or a : b :: c : d

⇒ 2 : 3 = 2 Extremes
3
here, ratio is simply a fraction and it has a : b = c : d
no unit

Means
c
or a b = ⇒ ad = bc
d
Equivalent Ratio’s Product of extremes = Product of Means
“If ratio’s can be expressed as one
common ratio then these ratio’s
are called equivalent ratio’s” Continued Proportion
4
1
1 4
i.e. , , 6 or = = 6
2 8 12 2 8 12 If a, b, c are in continued proportion
a
b
Then = ⇒ b = ac
2
b
c
Comparison of Ratio’s Profit
p r
If and are two ratio’s Simple Interest Here S.P. > C.P.
q
s
p r (by cross-multiplication) P × R × T Profit = S.P. – C.P.
q s S.I. = 100 Profit % = Profit × 100

If (p × s) > (q × r) A = P + S.I. C.P
p r Loss
then > s P Principal Here S.P. < C.P.
q
Rate
if (p × s) < (q × r) R Time Loss = C.P. – S.P.
T
p r Loss × 100
then < s A Amount Loss % = C.P
q