A classmate claims that using this food chain and assuming there is a 10% energy transfer rate , a snake would have to eat 10 frogs to get enough energy is this a correct understanding from your classmate?

No, this is not a correct understanding

Explanation:

Consider the food chain;

Grass → Grasshopper → Frog → Snake

In the food chain shown above, the grass is the producer, the grasshopper is the primary consumer, the frog is the secondary consumer while the snake is the tertiary consumer. Each step along the food chain is referred to as a trophic (feeding) level.

It is well known that at each trophic level, organisms utilize 90% of the energy they obtain for their metabolic activities. Only 10% of this energy is passed on to the next trophic level when the organism is eaten by other organisms at higher trophic levels. This is in accordance with the second law of thermodynamics.

The idea that on 10% of the energy at the second trophic level is passed on to the third trophic level does not mean that a snake must eat 10 frogs in order to acquire 10% of the energy in the organic molecules in frog. The 10% idea rather means that only 10% of the energy that the frogs obtained by eating grasshoppers is passed on to the snakes when snakes eat grasshoppers.