model 5 income & expenditure Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (c)

Using Rule 8,

Simple method

x = $(10/{100 + 10} × 100)$%

= $(1000/110)% = (100/11)% = 9{1}/11%$

Note : If A is r% more than B, then B is

$(r/{100 + r} × 100)$% less than A

Answer: (b)

Let B's salary = Rs.100

C's salary = Rs.400

and A's salary = Rs.40

Required percentage = $40/400 ×100$ = 10%

Answer: (d)

Let income be Rs.100

Sum given to elder son = 20% of Rs.100 = Rs.20

Remaining Sum = Rs. 80

Sum given to younger son = 30% of Rs.80 = Rs.24

Remaining sum = Rs.(80 – 24) = Rs. 56

Sum given to the trust = 10% of Rs.56 = Rs.5.6

Remaining sum = Rs.(56 – 5.6) = Rs.50.4

When Rs.50.4 remains, total income = Rs.100

When Rs.10080 remains, total income = ${100 × 10080}/50.4$ = Rs.20000

Here, R = Rs.10080; x = 20%, y = 30%, and z = 10%

Monthly income = $100/{100 – (20 +24 + 5.6)} ×10080$

= $1008000/{100 – 49.6} = 1008000/50.4 = 20,000$

Answer: (b)

Required percentage = $25/{100 + 25} × 100$

$25/125 × 100$ = 20%

Answer: (c)

Let man's salary be Rs.x.

His expenditure on items of daily use

= $25/2% of x ={25×x}/200 = x/8$

So, remaining amount

=$ x - x/8 = Rs.{7x}/8$

Expenditure on house rent

= 30% of Rs.${7x}/8$

$30/100 × {7x}/8 = Rs.{21x}/80$

Now, remaining amount = ${7x}/8 - {21x}/80$

= ${70x - 21x}/80 = Rs.{49x}/80$

According to the question,

${49x}/80 = 2940$

x =${2940 × 80}/49$ = Rs.4800

Aliter : Using Rule 20,

His salary = ${100 × 2940}/{100 – (25/2 + 26.25)}$

= ${100 × 2940}/{100 – (12.5+ 26.25)}$

= $294000/61.25$ = Rs.4800

Answer: (a)

Required percentage = $x/{100 - x} × 100$

= $40/60 × 100 = 200/3$= 66.66%