The temperature of the strips should decrease by 100 times the original length of the strips to make them have the same length.
To find out how much the temperature of the strips should be increased so that they have the same length, we can use the concept of thermal expansion.
The change in length of a material due to a change in temperature can be calculated using the equation:

Where:
= Change in length
= Original length of the material
= Coefficient of linear expansion
= Change in temperature
Given that the steel strip is 0.11% longer than the aluminum strip, and assuming both strips have the same original length,
let's denote the change in length of the aluminum strip as
and the change in length of the steel strip as
.
The change in length for the aluminum strip
can be represented as:

The change in length for the steel strip
can be represented as:

Given that the steel strip is 0.11% longer than the aluminum strip:

Now, we want to find the change in temperature
that would make the two strips have the same length. Since both strips start at the same temperature, we can set their change in lengths equal to each other:

Substituting the expressions for the change in lengths:


Solving for
:

Given the coefficients of linear expansion for steel (\
and aluminum
, which are approximately 12 ×
°C and 23 ×
°C respectively:

Now, substitute the values and solve for
:

(negative sign indicates that the change in temperature should be negative to achieve the desired result)
Therefore, The answer is 100 times.