Every train carriage has 4 doors how many doors will the train have if there are 7 carriages

28

Step-by-step explanation:

4*7=28

First write down the unit ratio that is involved.

In this case, it's train carriage/doors.

Next, we set up our proportion.

We know that for every train carriage, there are 4 doors.

So we have 1/4.

We are asked how many doors will there be is there are 7 carriages.

So we have 7/x.

The 7 must go on the top because our unit ratio says

that we must put train carriage/doors.

So we have 1/4 = 7/x.

Solving from here, we use the means-extremes property.

This states that the product of the extremes, (1)(x),

equals the product of the means, (4)(7).

So we have 1x = 28 or just x = 28.

This means that for 7 carriages, there are 28 doors.

percentage - 25%

probability - 0.25

we know,

total amount of students in class = 20

total boys = 10

total girls = 10

no of girls who wear glasses = 10/2 = 5

probability of choosing a girl with glasses is =

number of girls wearing glasses/total number of students in the class = 5/20

thus, percentage of selecting a girl wearing glasses will be

= 5/20 × 100

= 5 × 5

25%

therefore,

probability will be 0.25

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