Question

The mean leangth of 7 planks of wood is 1.3m .when an extra plank of wood increased to 1.4m what is the length of the extra plank of wood that has added​

Answer 1

SOLUTION

GIVEN

The mean length of 7 planks of wood is 1.3m .when an extra plank of wood added mean length increased to 1.4m

TO DETERMINE

The length of the extra plank of wood that has added

EVALUATION

Here it is given that the mean length of 7 planks of wood is 1.3m

So sum of the length of 7 planks of wood

= ( 7 × 1.3 )

= 9.1

Now an extra plank of wood added

Let the length = L metre

Now the total number of planks of wood

= 7 + 1

= 8

Now mean length increased to 1.4 m

So sum of the length of 8 planks of wood

= ( 8 × 1.4 )

= 11.2

Hence length of the extra plank of wood that has added

= 11.2 - 9.1

$= 2.1$

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