The ratio between boys and girls in a class is 3 : 1. Find the number of boys in the class is the total number of students is 40. ​

 30 boys

Step-by-step explanation:

Boys:Girls

3       : 1

Let no. of girls =x

⇒ no. of boys =3x.

⇒ no. of students in class =4x

                                            =   4/3×3x

                                            =  4 /3  ×no. of boys

  40=4/3* no.of boys

40* (3/4)=no.of boys

30=no of boys

b

step-by-step explanation:

30 miles

step-by-step explanation:

we know that 60 seconds equals 1 minute and 60 minutes 1 hour

44 ft       60 sec     60 min     158400   ft

  *   *   =

1 sec       1 min       1 hour         hour

we know that there are 5280 ft per mile

158400   ft       1 mile         30 miles

  *   =

1   hour               5280 ft     1 hour

so in 1 hour   it can travel 30 miles