IV. Solve the following:
1. Find the fourth proportional to 3kg, 12kg, 15kg
2. Rohan bought a calculator for ₹760 and sold it for₹ 874. Find his profit and profit
percentage.
3. 43% of the students in a school are girls. If the number of boys is 1482, find:
a. The total strength of the school
b. Number of girls in the school
4. By selling an almirah for 3906. Ravi suffers a loss of 294. Find the cost price
of the almirah and his loss percentage.
5. What number when increased by 30% becomes 39 ?
Answers
Step-by-step explanation:
(1) 3:12::15: X
Product of outer term= product of means term
3x=12×15
3X=180
X=180/3
X=60
(2). cost price of calculator = 760
selling price= 874
profit= selling price - cost price
874-760
profit= 114
Profit%=( Profit × 100)/ cost price
Profit%= { 114×100}\760
P%= 15%
(3). Percentage of girl in school= 43%
Percentage of boys= 100-43= 57%
number of boys = 1482
57 of girl of = 1482
total students= (1482×100)/57
total students= 2600
number of girl is = 2600- 1482= 1118
(4). Selling price of almirah= 3906
loss= 294
cost price= Selling price+ loss
3906+294
cp= 4200
loss% = (loss × 100)/ cost price
loss% (294×100)/4200
loss% = 7%
(5). Let the number be x
According to statement,
x+30% of x=39
x+30x/100 =39
(100x+30x)/100= 39
130x/100= 39
X= (39×100)/130
X =30