YOU CAN DOWNLOAD 200+ SUBJECTS PDF BOOK FOR COMPETITIVE EXAMINATIONS
Ratio
Question 106 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
If a : b = b : c, then a4 : b4 is equal to =?
c2 : a2 | |
ac = b2 | |
b2 : ac | |
a2 : c2 |
Question 106 Explanation:
\begin{align} & a:b = b:c \cr & \frac{a}{b} = \frac{b}{c} \cr & {b^2} = ac \cr & {b^4} = {a^2}{c^2} \cr & \therefore {a^4}:{b^4} = \frac{{{a^4}}}{{{b^4}}} \cr & \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, = \frac{{{a^4}}}{{{a^2}{c^2}}} \cr & \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, = \frac{{{a^2}}}{{{c^2}}} \cr & \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, = {a^2}:{c^2} \cr\end{align}
Question 107 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
Two numbers are respectively 20% and 50% more than a third number. The ratio of the two numbers is:
3 : 5 | |
6 : 7 | |
2 : 5 | |
4 : 5 |
Question 107 Explanation:
\begin{align} & {\text{Let}}\, {\text{the}}\, {\text{third}}\, {\text{number}}\, {\text{be}}\, x. \cr & {\text{Then, }}\, {\text{first}}\, {\text{number}} \cr & = 120\% \, {\text{of}}\, x = \frac{{120x}}{{100}} = \frac{{6x}}{5} \cr & {\text{Second}}\, {\text{number}} \cr & = 150\% \, {\text{of}}\, x = \frac{{150x}}{{100}} = \frac{{3x}}{2} \cr & \therefore {\text{Ratio}}\, {\text{of}}\, {\text{first}}\, {\text{two}}\, {\text{numbers}} \cr & = \left( {\frac{{6x}}{5}:\frac{{3x}}{2}} \right) = 12x:15x = 4:5. \cr\end{align}
Question 108 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
If A:B = 2:3 and B:C = 4:5 then A:B:C is
8:12:15 | |
5:4:6 | |
6:4:5 | |
2:3:5 |
Question 108 Explanation:
A/B = 2/3;
B/C = 4/5;
A:B:C = 2*4:3*4:3*5 = 8:12:15.
Question 109 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
A and B are two alloys in which ratios of gold and copper are 5:3 and 5:11 respectively. If these equally amount of two alloys are melted and made alloy C. What will be the ratio of gold and copper in alloy C?
15 :17 | |
33 :25 | |
25 :23 | |
17 :15 |
Question 109 Explanation:
Ratio of Gold and Copper in Alloy A = 5 : 3
Ratio of Gold and Copper in Alloy B = 5 :11
Amount of Gold in Alloy A = 5/8
Amount of Gold In Alloy B = 5/16
Amount of Copper in A = 3/8
Amount of Copper in B = 11/16
Amount of Gold In C,
= (Amount of gold in A + Amount of gold in B) = (5/8) +(5/16) = (10+5)/16 = 15/16.
Amount of Copper in C,
= Amount of Copper in A + Amount of Copper in B = (3/8) + (11/6) = 17/16.
So,
Ratio of Gold and Copper in C,
= 15/16 : 17/16 = 15 :16
Question 110 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
Two numbers are respectively 20 percent and 50 percent more than a third number. These two numbers are in the ratio.
3 : 5 | |
6 : 7 | |
2 : 5 | |
4 : 5 |
Question 110 Explanation:
\begin{align} & {\text{Let the third number be }}x. \cr & {\text{Then, }} \cr & {\text{first number}} \cr & = 120\% {\text{ of }}x = \frac{{120}}{{100}}x = \frac{{6x}}{5}. \cr & {\text{And, second number}} \cr & = 150\% {\text{ of }}x = \frac{{150}}{{100}}x = \frac{{3x}}{2}. \cr & \therefore {\text{Required ratio}} \cr & = \frac{{6x}}{5}:\frac{{3x}}{2} \cr & = 12:15 \cr & = 4:5. \cr\end{align}
There are 110 questions to complete.