Tag: ratio, proportion and unitary method

Questions Related to ratio, proportion and unitary method

In a box, the ratio of the number of red marbles to that of blue marbles is $4 : 7$. which of the following could be the total number of in the box?

maths ratio, proportion and unitary method converting to ratios finding ratios other quantities

  1. $14$

  2. $21$

  3. $22$

  4. $28$

Show answer
Correct Option: C
Explanation:

$With\quad ratios,add\quad all\quad the\quad parts\quad together\quad to\quad get\quad a\quad total.In\quad this\quad case,it\quad is\quad 4red\quad and\quad 7blue.$


$7+4=11.$

$Therefore,the\quad lowest\quad total\quad number\quad of\quad marbles\quad is11.The\quad answer\quad will\quad be\quad any\quad number\quad divisible\quad by\quad 11.$

$Hence\quad it\quad is\quad 22.$

If A : B = 7 : 5 and B : C = 9 : 11, then A : B : C is equal to

maths ratio, proportion and unitary method converting to ratios finding ratios other quantities

  1. 55:45:63

  2. 63:45:55

  3. 45:63:55

  4. None of these

Show answer
Correct Option: B
Explanation:

$A:B=7:5\B:C=9:11$

Let $A=7p, B=5p\B=9q,C=11q\\because 5p=99\ \therefore p=\cfrac{99}{5}\ \therefore A=7\times\cfrac{99}{5}=\cfrac{639}{5}\ \therefore A:B:C=\cfrac{639}{5}:9q:11q\A:B:C=63:45:55$
Option B

The ratio of $\left(\displaystyle\dfrac{1}{3}\text{ of Rs. }9.30\right)$ to $(0.6\text{ of Rs. }1.55)$ is ___________.

maths ratio, proportion and unitary method converting to ratios finding ratios other quantities

  1. $1:3$

  2. $10:3$

  3. $3:10$

  4. $3:1$

Show answer
Correct Option: B
Explanation:

$\displaystyle\frac{1}{3}$ of Rs. $9.30=Rs. \left(\displaystyle\frac{1}{3}\times 9.30\right)=Rs. 3.10$
$0.6$ of Rs. $1.55=$Rs. $(0.6\times 1.55)=$ Rs. $0.93$
$\therefore$ Required ratio$=3.10:0.93=10:3$.

Cost of a candy is $50$ paise and cost of an ice cream is Rs. $20$, then the ratio of the cost of a candy to the cost of an ice-cream is __________.

maths ratio, proportion and unitary method converting to ratios finding ratios other quantities

  1. $40:1$

  2. $1:40$

  3. $1:20$

  4. $1:15$

Show answer
Correct Option: B
Explanation:

Cost of $1$ candy $=50$ paise
Cost of $1$ ice-cream $=Rs. 20=20\times 100$ paise
$=2000$ paise
$\therefore$ Required ratio $=50:2000=1:40$.

Out of $30$ students in a class, $6$ like football, $12$ like cricket and remaining like tennis. The ratio of number of students who like tennis to the total number of students, is:

maths ratio, proportion and unitary method converting to ratios finding ratios other quantities

  1. $2:3$

  2. $5:1$

  3. $2:5$

  4. $5:2$

Show answer
Correct Option: C
Explanation:
Total number of students$=30$
Number of students who like football$=6$
Number of students who like cricket$=12$
$\therefore$ Number of students who like tennis $=30-6-12=12$
$\therefore$ Required ratio $=12:30=2:5$.