Question

In a fish tank, 65% is female fishes. The rest are male. Female fishes are also 15 less than twice of male fishes. How many female fishes and male fishes in the tank ?

Answer 1

Answer:

There are 105 male fishes and 195 female fishes

Step-by-step explanation:

Let

x-----> the number of female fishes

y-----> the number of male fishes

we know that

65%=65/100=0.65

so

x=0.65(x+y) ----> equation A

x=2y-15 ----> equation B

substitute equation B in equation A and solve for xy

2y-15=0.65(2y-15+y)

2y-15=1.30y-9.75+0.65y

2y-15=1.95y-9.75

2y-1.95y=-9.75+15

0.05y=5.25

y=105 male fishes

Find the value of x

x=2(105)-15=195 female fishes

Answer 2

The number of female fishes and male fishes in the tank are 195 and 105 respectively.

How to solve equation

Let

x = the number of female fishes

y = the number of male fishes

Female = 65%

65% = 65/100

=0.65

The equation

x = 0.65(x + y) (1)

x = 2y - 15. (2)

• substitute equation 2 in equation 1

2y - 15= 0.65(2y - 15 + y)

2y - 15 = 1.30y - 9.75 + 0.65y

2y - 15 = 1.95y - 9.75

• collect like terms

2y - 1.95y = -9.75 + 15

0.05y = 5.25

y = 105 male fishes

• Substitute for the value of x

x = 2(105) - 15

= 195 female fishes

Learn more about equation:

https://brainly.com/question/1214333