Hey,

Do you have any other aoe damaging ninjas such as Hokage Minato for example or Jonin Minato?

Gaara is pretty much crucial in the exam, he can do a lot of damage and you mostly need clones. Try out a team with Wind Main, Gaara, Minato and one more ninja that can support you or do some damage, for example Guy Hirodora with them. Clones are pretty much going to tank the attacks till you bring down most of them. Make sure to cast Gaara the right timing on round 1 and additionally, round 2 to generate some chakra and to fire Gaara.

In case you got Madara he works much better as well.

Hope that helps. Try it out and if you got any trouble feel free to pm me