how to multiply in PHP?

[Designinfo]

I want the final amount posted to be multiplied by 1.02

The following is the payment.php of the PAYUMONEY zip file

$ total has to be multiplied by 1.02

 

I dont know if this is the right way but I am attaching the entire module also.I want the final amount posted on the Payumoney website multiplied by 1.02   

 

Reason I want to add a tax on payment by credit card tax of 2%

 

 

$payu = new payu();

$context = Context::getContext();

$cart = $context->cart;

 

 

 

if (!$cookie->isLogged(true))

Tools::redirect('authentication.php?back=order.php');

elseif (!$cart->getOrderTotal(true, Cart::BOTH))

Tools::displayError('Error: Empty cart');

 

if ($cart->id_customer == 0 OR $cart->id_address_delivery == 0 OR $cart->id_address_invoice == 0 OR !$payu->active)

Tools::redirectLink(__PS_BASE_URI__.'order.php?step=1');

 

 

 

 

// Prepare payment

 

$customer = new Customer((int)$cart->id_customer);

 

if (!Validate::isLoadedObject($customer))

Tools::redirectLink(__PS_BASE_URI__.'order.php?step=1');

 

$currency = new Currency(Tools::getValue('currency_payement', false) ? Tools::getValue('currency_payement') : $cookie->id_currency);

$total = (float)($cart->getOrderTotal(true, Cart::BOTH));

 

 

 

$payu->validateOrder($cart->id, Configuration::get('PS_OS_BANKWIRE'), $total, $payu->displayName, NULL,NULL, (int)$currency->id, false, $customer->secure_key);

Tools::redirect('index.php?controller=order-confirmation&id_cart='.(int)$cart->id.'&id_module='.$payu->id.'&id_order='.$payu->currentOrder.'&key='.$customer->secure_key);

include('../../footer.php');

payu.zip

[vekia]

if you want multiply total variable just use

$total = $total * 1.02;

[Designinfo]

which part of the code do I enter that?

Not working