At 22:58 on Thursday, 1 June 2006 Ben said:

That doesn’t make sense…

It's time for some maths. Let us consider the following:

Ss = total stanford students
Se = stanford students who are engineers
So = stanford students who are other majors
Tt = total tango students
Te = tango students who are engineers
To = tango students who are other majors

We know:
20% of standford students are engineers
Therefore 80% of standford students are other majors

Using our symbols from above:
Se = 0.2 Ss ... (1)
So = 0.8 Ss ... (2)

We also know:
40% of his students are engineers then....
Therefore 60% of his students are other majors

Again from our symbols:
Te = 0.4 Tt ... (3)
To = 0.6 Tt ... (4)

Thus the proportion of engineering students at stanford who are also tango students is (3) divided by (1):

Te/Se = 0.4 Tt / 0.2 Ss

rearrange:

Tt/Ss = 0.5 Te/Se ... (5)

The proportion of other majors at stanford who are also tango dancers is (4) divided by (2):

To/So = 0.6 Tt / 0.8 Ss

rearrange:

Ss/Tt = 1.33 To/So ... (6)
Combining (5) and (6) gives:

0.5Te/Se = 1.33To/So

or:
Te/Se = 2.66 To/So

This latter equation, in english, says the number of engineering tango dancers as a proportion of total stanford engineering majors is equal to 2.66 times the number of other major tango dancers as a proportion of total stanford students doing other majors... He said it was 2...

If he were right, then he'd actually have 120% of a class of students. That would be very cool. I will leave this latter part as an exercise for the reader to confirm!

At 16:53 on Friday, 2 June 2006 Ana said:

Tango needs more electricians. They use their left brain too and my light fittings need to be changed.